Travis-ci only makes secure environment variables available when
merging from a branch. This change allows the test coverage to
continue to be calculated, even when merging from a fork.
Coverage remained the same when pulling 03dbf7b0564a979f6725c85a60b3c32ff4b9e956 on only-coverage-on-branch into 22f6e709c4df7bf74a7853cbd723984aa2e97522 on master.
Travis-ci only makes secure environment variables available when merging from a branch. This change allows the test coverage to continue to be calculated, even when merging from a fork.