dlm: use rsbtbl as resource directory

Remove the dir hash table (dirtbl), and use
the rsb hash table (rsbtbl) as the resource
directory.  It has always been an unnecessary
duplication of information.

This improves efficiency by using a single rsbtbl
lookup in many cases where both rsbtbl and dirtbl
lookups were needed previously.

This eliminates the need to handle cases of rsbtbl
and dirtbl being out of sync.

In many cases there will be memory savings because
the dir hash table no longer exists.

Signed-off-by: David Teigland <teigland@redhat.com>

fs/dlm/config.h

@@ -27,7 +27,6 @@ struct dlm_config_info {
 	int ci_tcp_port;
 	int ci_buffer_size;
 	int ci_rsbtbl_size;
-	int ci_dirtbl_size;
 	int ci_recover_timer;
 	int ci_toss_secs;
 	int ci_scan_secs;