story #3226 - Update SVN log messages.

Project admins can enable "Modify the commit messages".
Then everyone with write access on repo can update any commit message. This
modification is applied on Subversion history as well as in the database.

The "Mandatory Reference in commit message" property is checked and cross
references are updated as well.

Change-Id: I3f3a7db52e8e8485ceb10b3d2d20b0e81a1a2eb2
Merge commit 'refs/changes/31/431/4' of http://gerrit.tuleap.net/tuleap into tuleap-stable-master

* http://gerrit.tuleap.net/tuleap:
  story #3226 - Update SVN log messages.

Change-Id: Iee2da059167c3cafbf1873a9c5a0e2549728a14b
Tuleap 6.0.99.2

Change-Id: I3fac7a1205bd46f3adc8a0371e4222a9f83cb070