ctdb-scripts: Switch NFS checks to new style

ctdb-scripts: Switch NFS checks to new style

Note that the 60.ganesha RPC checks need to be identical to those in
the nfs-checks.d/ directory.  This is because the NFS unit test
infrastructure checks output against what should be produced by the
checks in nfs-checks.d/.  This is a minor issue, since one of the aims
of this work is to remove the need for a separate 60.ganesha.

In most cases configuration variable CTDB_NFS_DUMP_STUCK_THREADS is
now ignored.  This is now handled by passing the desired number of
threads to the command specified in the service_debug_cmd variable in
a .check file.

Signed-off-by: Martin Schwenke <martin@meltin.net>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>