ocfs2: Pass the locking protocol into ocfs2_cluster_connect().

Inside the stackglue, the locking protocol structure is hanging off of
the ocfs2_cluster_connection.  This takes it one further; the locking
protocol is passed into ocfs2_cluster_connect().  Now different cluster
connections can have different locking protocols with distinct asts.
Note that all locking protocols have to keep their maximum protocol
version in lock-step.

With the protocol structure set in ocfs2_cluster_connect(), there is no
need for the stackglue to have a static pointer to a specific protocol
structure.  We can change initialization to only pass in the maximum
protocol version.

Signed-off-by: Joel Becker <joel.becker@oracle.com>