CBQE-927: skip teardown if test failed for python2.6

upgrade tests

Change-Id: Id50b00baee79b92d8c9b7c00f8eb6d54040b0c62
Reviewed-on: http://review.couchbase.org/25010
Tested-by: buildbot <build@couchbase.com>
Reviewed-by: Andrei Baranouski <andrei.baranouski@gmail.com>