BUG/MINOR: threads: Don't forget to init each thread toremove_lock.

Don't forget to use HA_SPIN_INIT() on each toremove_lock, or DEBUG_THREAD may
not work reliably with it.

This should be backported to 2.1 and 2.0.

src/cfgparse.c

@@ -3571,6 +3571,7 @@ out_uri_auth_compat:
 							goto err;
 						idle_conns[i].cleanup_task->process = srv_cleanup_toremove_connections;
 						idle_conns[i].cleanup_task->context = NULL;
+						HA_SPIN_INIT(&idle_conns[i].toremove_lock);
 						MT_LIST_INIT(&idle_conns[i].toremove_conns);
 					}
 				}