Fix buck build

Bring up to date with latest version gerrit.  It was failing with
following messages:

* TypeError: java_test() got an unexpected keyword argument 'source_under_test'
* No build file at lib/jgit/BUCK when resolving target //lib/jgit:jgit

Change-Id: Ic6372e1275c11aaf9a513cb161e1ba3e17a9a35b