Removes `github.com/sqs/go-selfupdate` as dependency.

[chris-ramon]

Details

• [x] Removes github.com/sqs/go-selfupdate as dependency because is not required upstream anymore:
  • Removes selfupdate_cmd
  • Updates vendor.json
  • Updates Makefile

---

Test plan

• [x] Confirm that upstream related command: make clean && make srclib works fine locally:

  (dockerfiles)-> pwd
  /home/chris/go_packages/src/sourcegraph.com/sourcegraph/sourcegraph/services/worker/dockerfiles
  (dockerfiles)-> make clean && make srclib
  rm -f ./srclib
  Sending build context to Docker daemon 332.3 kB
  Step 1 : FROM golang:1.6-alpine
  ---> b0d7017acee6
  Step 2 : RUN apk --update add git make
  ---> Using cache
  ---> 580f3cae41a7
  Step 3 : ARG URL
  ---> Using cache
  ---> bd903d32c569
  Step 4 : ADD $URL /toolchain/t
  Downloading 990.4 kB
  ---> Using cache
  ---> 26d66267cd3d
  Step 5 : RUN (cd /toolchain && tar xfz t && rm t && mv * t) || true
  ---> Using cache
  ---> 2864cefedac4
  Step 6 : RUN mkdir -p $GOPATH/src/sourcegraph.com/sourcegraph && mv /toolchain/t $GOPATH/src/sourcegraph.com/sourcegraph/srclib
  ---> Using cache
  ---> de70e58be424
  Step 7 : WORKDIR $GOPATH/src/sourcegraph.com/sourcegraph/srclib
  ---> Using cache
  ---> 506f9f37807e
  Step 8 : RUN go get github.com/laher/goxc
  ---> Using cache
  ---> 8fb23a9c4290
  Step 9 : RUN make govendor
  ---> Using cache
  ---> d8cf619c29a3
  Step 10 : RUN goxc -q
  ---> Using cache
  ---> bde26233fa91
  Step 11 : VOLUME /out
  ---> Using cache
  ---> 490a212723fb
  Step 12 : ENTRYPOINT mv ./release/snapshot/linux-amd64 /out/srclib
  ---> Using cache
  ---> be0155ba25d0
  Successfully built be0155ba25d0
  docker run -v /home/chris/go_packages/src/sourcegraph.com/sourcegraph/sourcegraph/services/worker/dockerfiles:/out sourcegraph/srclib

[beyang]

great, thanks for submitting this.