cephfs: replace tests mount setup boilerplate with func
cephfs: replace tests mount setup boilerplate with func

In the cephfs tests the setup of the mount/connection was largely being
done as a copy-n-paste. This change adds a common setup function for
most of the test cases that need an active connection.
Similar to other recent changes this also adds a timeout such that
if the test fails to get a connection it will fail quickly rather
than block forever.

Signed-off-by: John Mulligan <eda8ad33169deab44f9fe65847f99e368da6c91b@redhat.com>

ceph/go-ceph,ceph/go-ceph,ceph/go-ceph