fs/dlm: Drop unnecessary null test

hlist_for_each_entry binds its first argument to a non-null value, and thus
any null test on the value of that argument is superfluous.

The semantic patch that makes this change is as follows:
(http://coccinelle.lip6.fr/)

// <smpl>
@@
iterator I;
expression x,E,E1,E2;
statement S,S1,S2;
@@

I(x,...) { <...
- (x != NULL) &&
  E
  ...> }
// </smpl>
Signed-off-by: Julia Lawall <julia@diku.dk>
Signed-off-by: David Teigland <teigland@redhat.com>

fs/dlm/lowcomms.c

@@ -248,7 +248,7 @@ static struct connection *assoc2con(int assoc_id)
 
 	for (i = 0 ; i < CONN_HASH_SIZE; i++) {
 		hlist_for_each_entry(con, h, &connection_hash[i], list) {
-			if (con && con->sctp_assoc == assoc_id) {
+			if (con->sctp_assoc == assoc_id) {
 				mutex_unlock(&connections_lock);
 				return con;
 			}