BUG-976: jenkins slowed down by dowload from nexus

- removed opendaylight.release repository (contained in groups/public)

Change-Id: I190e3ccd9482ab58dd5502567b4d2a7e14b5e68f
Signed-off-by: Michal Rehak <mirehak@cisco.com>
Merge "BUG-976: jenkins slowed down by dowload from nexus"