teuthology/suite/test: make sure patchers are cleaned up on exception
teuthology/suite/test: make sure patchers are cleaned up on exception

Otherwise, test infrastructure blows up on use of the fake file system
methods.

Signed-off-by: Patrick Donnelly <d35c2028e065409a3eff47e1b4cba347a9379b4b@redhat.com>

ktdreyer/teuthology,ceph/teuthology,ktdreyer/teuthology,ceph/teuthology