Prevent timeout - only build default version
Prevent timeout - only build default version

The ci.jenkins.io infrastructure is configured to timeout a job after
60 minutes.  That is a very reasonable timeout, but the Windows and
Linux execution of the git client plugin sometimes exceeds 30 minutes
for a single Jenkins version, so it can exceed 60 minutes when testing
the default version and the latest LTS.

MarkEWaite/git-client-plugin,MarkEWaite/git-client-plugin,MarkEWaite/git-client-plugin