tests: Add spaces around '=' in a string comparision in TEST primitive

Change-Id: I0402949c8cd88cc93e073a7c8ae60b5ff4497ad2
BUG: 764966
Signed-off-by: Kaushal M <kaushal@redhat.com>
Reviewed-on: http://review.gluster.org/4538
Reviewed-by: Krishnan Parthasarathi <kparthas@redhat.com>
Tested-by: Gluster Build System <jenkins@build.gluster.com>