Remove flush locking functionality

This just seemed like more trouble that it was worth. Flush locks were
originally intended as a way to counteract the weird issues around
flushing that were mostly fixed by the code refactoring, so this will
help test if those issues are truly gone. If not, will look into a
cleaner solution that doesn't result in unchangeable states.

client-cli/pvc.py

@@ -1648,8 +1648,6 @@ def init_cluster(yes):
     transaction.create('/ceph/pools', ''.encode('ascii'))
     transaction.create('/ceph/volumes', ''.encode('ascii'))
     transaction.create('/ceph/snapshots', ''.encode('ascii'))
-    transaction.create('/locks', ''.encode('ascii'))
-    transaction.create('/locks/flush_lock', 'False'.encode('ascii'))
     transaction.commit()
 
     # Close the Zookeeper connection