mr approve: Fix unapprove test failures
mr approve: Fix unapprove test failures

The mr approve and unapprove tests cannot be run in parallel.

Remove the parallel call in the test.

Signed-off-by: Prarit Bhargava <fe4655370dc87a32329d591d6e8472329333dfad@redhat.com>

zaquestion/lab,zaquestion/lab