As discussed on the jgit-dev list here:
http://dev.eclipse.org/mhonarc/lists/egit-dev/msg00654.html



- Define a separate JGit feature.
- As of now create a separate JGit update site and zip it.

Change-Id: Ie4026f15f6250c4933dccf6f31b5009b90c036bc
Signed-off-by: Matthias Sohn <matthias.sohn@sap.com>