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.

(cherry picked from commit f21695bd8b59d582efc99c85f9a1afac200eda81)
[wt: the lock is called toremove_lock[i] in 2.1]
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 00e12621af67f03e27b47d77227fa598efe12cc6)
[wt: context adj]
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/src/cfgparse.c b/src/cfgparse.c
index 3850786..a646405 100644
--- a/src/cfgparse.c
+++ b/src/cfgparse.c
@@ -3703,6 +3703,7 @@
 							goto err;
 						idle_conn_cleanup[i]->process = srv_cleanup_toremove_connections;
 						idle_conn_cleanup[i]->context = NULL;
+						HA_SPIN_INIT(&toremove_lock[i]);
 						LIST_INIT(&toremove_connections[i]);
 					}
 				}