switch to c:select to support in-place addition of credentials
[FIXED JENKINS-20561] fix migration of skipTag property for job using configuration format version 1
Merge pull request #179 from ydubreuil/fix-JENKINS-20561

[FIXED JENKINS-20561] fix migration of skipTag property for job using configuration format version 1
If !skipTag, PerBuildTag is added, so test with it true.
Working towards making it possible to test this plugin against newer Jenkins cores using plugin-compat-tester.
Changed to allow creating RevisionParameterAction using existing Revision, from a previous build for example. This provides the sha1, branches, etc. as they exist in the Revision for the parameter action on the new build.
Merge pull request #182 from daldinger/RevParms

Changed to allow creating a RevisionParameterAction using an existing Revision
[JENKINS-20502] enforce configured refspecs have been fetched
clone don't handle custom refspecs, so need to run fetch
[JENKINS-20318] use git-credentials-store
set remote.<name>.url
now that git-client 1.5.x stop exposing credentials in .git/config 
(thanks to git-credentials) we can set remote.<name>.url
this fix broken GitPublisher
Make checkout lock failure retryable.