Update joda-time to 2.6
Update junit dependency to 4.12
Update mockito-all dependency to 1.10.17
Update credentials to 1.19
Update git-client dependency to 1.13.0 - CVE-2014-9390

Also updates to JGit 3.5.3.

Refer to http://article.gmane.org/gmane.linux.kernel/1853266 for a
description of the client side bug which is resolved by JGit 3.5.3.

It seems unlikely the client side bug will affect many Jenkins users
due to the relatively limited workflow used in the git client plugin
and the git plugin.
JENKINS-25048: Added filters check for notifyCommit event