sharder: fix probe tests skipping conditions
sharder: fix probe tests skipping conditions

Previously all sharder probe tests were skipped if auto-sharding was
not configured for the test cluster. This is now fixed so that only
tests that require auto-sharding are skipped.

Change-Id: Icefc6441f8d48a0d418a4ab70b778b48ffdcbb59

openstack/swift,tipabu/swift,openstack/swift,openstack/swift,tipabu/swift,tipabu/swift,tipabu/swift,openstack/swift