tests: move common funtion definitions to include.rc

BUG: 765473
Change-Id: Id0d194374d34cfec8ee601090f7fe38b1856ac22
Signed-off-by: Raghavendra G <raghavendra@gluster.com>
Reviewed-on: http://review.gluster.org/4631
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Jeff Darcy <jdarcy@redhat.com>