Update jenkins.js

[hipstersmoothie]

Trying to use env-ci in a multi-branch pipeline jenkins project. The main problem I have run into is that jenkins will make it's own branch when building (e.g PR-123). This is not the name of the actual branch it's building, and anything that tries to use the branch name will fail

https://ci.eclipse.org/webtools/env-vars.html/

Solution

Use the CHANGE_BRANCH env var

CHANGE_BRANCH

For a multibranch project corresponding to some kind of change request, this will be set to the name of the actual head on the source control system which may or may not be different from BRANCH_NAME. For example in GitHub or Bitbucket this would have the name of the origin branch whereas BRANCH_NAME would be something like PR-24.

[gr2m]

Hi @hipstersmoothie, if you'd still like this change to be merged, could you please rebase on latest master and also update the tests to reflect your change, so we avoid future regressions?