509269 Simple paged result crashes/hangs the server

There was a contention between the connection table cleanup thread (main)
and the search thread.  The cleanup code should have been protected by
the same mutex we do in the paged result code (c_mutex).

ldap/servers/slapd/conntable.c

@@ -312,7 +312,9 @@ connection_table_move_connection_out_of_active_list(Connection_Table *ct,Connect
 
     connection_release_nolock (c);
 
+    PR_Lock(c->c_mutex);
     connection_cleanup (c);
+    PR_Unlock(c->c_mutex);
 
     PR_Unlock(ct->table_mutex);