CBQE-0: py-xdcr-bidirectional doesn't contain expiration tests

I do not exclude that some tests failed due to timeout, but we should have such tests

Change-Id: I5e06705c6884c70697d45f465784e634f11bd866
Reviewed-on: http://review.couchbase.org/32989
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Sangharsh Agarwal <sangharsh.agarwal@globallogic.com>