vendoring fails when run `make vendor`

I tried to vendor the codebase with error of missing repo github.com/coreos-inc/tectonic-operators, my guess is that this repo is private and is only accessible to certain people. Can this code be made available if it is private or change the Gopkg link to the approproate location.
$ make vendor                                 
/home/hummer/go/bin/dep ensure -v -vendor-only
(1/69) Wrote github.com/PuerkitoBio/purell@v1.1.0   
(2/69) Wrote github.com/go-openapi/swag@master                                                           
(3/69) Wrote github.com/PuerkitoBio/urlesc@master   
(4/69) Wrote github.com/davecgh/go-spew@v1.1.0                                                                        
(5/69) Wrote github.com/go-openapi/jsonreference@master                                                  
(6/69) Wrote github.com/beorn7/perks@master         
(7/69) Wrote github.com/pmezard/go-difflib@v1.0.0   
(8/69) Wrote github.com/coreos/go-semver@v0.2.0     
(9/69) Wrote github.com/go-openapi/loads@master     
(10/69) Wrote github.com/asaskevich/govalidator@v8                                                       
(11/69) Wrote k8s.io/kube-openapi@master            
(12/69) Wrote github.com/go-openapi/strfmt@master
(13/69) Wrote github.com/go-openapi/runtime@master  
(14/69) Wrote github.com/golang/glog@master         
(15/69) Wrote github.com/golang/groupcache@master                                                        
(16/69) Wrote github.com/ghodss/yaml@v1.0.0         
(17/69) Wrote github.com/go-openapi/errors@master
(18/69) Wrote github.com/gorilla/mux@v1.6.1         
(19/69) Wrote github.com/google/gofuzz@master       
(20/69) Wrote github.com/howeyc/gopass@master                                                            
(21/69) Wrote github.com/pmorie/go-open-service-broker-client@0.0.5                                      
(22/69) Wrote github.com/prometheus/client_golang@v0.8.0
(23/69) Wrote github.com/go-openapi/analysis@master
(24/69) Wrote github.com/imdario/mergo@0.3.2
(25/69) Wrote github.com/gorilla/context@v1.1
(26/69) Wrote github.com/golang/protobuf@v1.0.0
(27/69) Wrote github.com/prometheus/client_model@master
(28/69) Wrote github.com/go-openapi/validate@master
(29/69) Wrote github.com/gregjones/httpcache@master
(30/69) Wrote github.com/hashicorp/golang-lru@master
(31/69) Failed to write github.com/coreos-inc/tectonic-operators@beryllium-m1
(32/69) Failed to write github.com/google/btree@master
(33/69) Failed to write github.com/modern-go/concurrent@1.0.3
(34/69) Failed to write github.com/sirupsen/logrus@v1.0.4
(35/69) Failed to write github.com/juju/ratelimit@1.0.1
(36/69) Failed to write github.com/pmorie/osb-broker-lib@0.0.3
(37/69) Failed to write github.com/emicklei/go-restful@v2.6.0
(38/69) Failed to write github.com/prometheus/common@master
(39/69) Failed to write github.com/matttproud/golang_protobuf_extensions@v1.0.0
(40/69) Failed to write github.com/json-iterator/go@1.1.2
(41/69) Failed to write github.com/prometheus/procfs@master
(42/69) Failed to write github.com/golang/mock@v1.0.0
(43/69) Failed to write github.com/mitchellh/mapstructure@master
(44/69) Failed to write github.com/mailru/easyjson@master
(45/69) Failed to write github.com/go-openapi/spec@master
(46/69) Failed to write github.com/googleapis/gnostic@v0.1.0
(47/69) Failed to write github.com/gogo/protobuf@v1.0.0
grouped write of manifest, lock and vendor: error while writing out vendor tree: failed to write dep tree: failed to export github.com/coreos-inc/tectonic-operators: no valid source could be created:
        failed to set up sources from the following URLs:
https://github.com/coreos-inc/tectonic-operators
: remote repository at https://github.com/coreos-inc/tectonic-operators does not exist, or is inaccessible: fatal: could not read Username for 'https://github.com': terminal prompts disabled
: exit status 128
        failed to set up sources from the following URLs:
ssh://git@github.com/coreos-inc/tectonic-operators
: remote repository at ssh://git@github.com/coreos-inc/tectonic-operators does not exist, or is inaccessible: ERROR: Repository not found.
fatal: Could not read from remote repository.

Please make sure you have the correct access rights
and the repository exists. 
: exit status 128
        failed to set up sources from the following URLs:
git://github.com/coreos-inc/tectonic-operators
: remote repository at git://github.com/coreos-inc/tectonic-operators does not exist, or is inaccessible: fatal: remote error:
  Repository not found.
: exit status 128                             
        failed to set up sources from the following URLs:
http://github.com/coreos-inc/tectonic-operators
: remote repository at http://github.com/coreos-inc/tectonic-operators does not exist, or is inaccessible: fatal: could not read Username for 'https://github.com': terminal prompts disabled
: exit status 128
make: *** [Makefile:112: vendor] Error 1
operator-framework / operator-lifecycle-manager

vendoring fails when run `make vendor` #350
