core: Add no-arg constructor to AddInternalJobParameters

This is required in order to avoid potential serialization
issues with GWT RPC.

Change-Id: Ic6d6ac2db61e8336b419a036033248a8b4f380c6
Bug-Url: https://bugzilla.redhat.com/1015683
Signed-off-by: Vojtech Szocs <vszocs@redhat.com>