Note: I'm still seeing this behavior, after having updated from Jenkins 2.2 to Jenkins 2.60.3.
I am using ruby-runtime 0.12, but the behavior still occurs - on boot, the buildWrappers sections of any older jobs is deleted - removing RVM, but also ANSI-color plugins, and others.
Any ideas on how to fix this?
If I create a new job, it seems to be created correctly... I am looking for a work-around that doesn't involve updating all of my jobs by hand.
Edit: I found this, in the readme:
We were using a very old version of RVM plug-in, and need to execute these update instructions before upgrading to the new plugin version.