Retry parameter fix (JENKINS-18759)

This is a speculative pull request. I'm hoping it will stimulate some discussion leading to an improved version suitable for merging.

This is an attempt at fixing this defect:
https://issues.jenkins-ci.org/browse/JENKINS-18759

I'm not sure why there are several different build triggering methods in the pipeline plugin, but switching the retry action to use the same method as manual triggering seems to resolve this issue.

Would appreciate some feedback as to whether this is a viable option.