MINOR: memory: Only init the pool spinlock once.

In pool_create(), only initialize the pool spinlock if we just created the
pool, in the event we're reusing it, there's no need to initialize it again.

(cherry picked from commit 8af97eb4a19c1d3c0849b5e5e5d350d63f819032)
Signed-off-by: Willy Tarreau <w@1wt.eu>
(cherry picked from commit 3c5e337c74a07ca2db2ac0997ee4d89c7969c80b)
Signed-off-by: Willy Tarreau <w@1wt.eu>
diff --git a/src/memory.c b/src/memory.c
index 7a5aa74..07e3428 100644
--- a/src/memory.c
+++ b/src/memory.c
@@ -139,11 +139,11 @@
 			for (thr = 0; thr < MAX_THREADS; thr++)
 				pool_cache[thr][idx].size = size;
 		}
-	}
-	pool->users++;
 #ifndef CONFIG_HAP_LOCKLESS_POOLS
-	HA_SPIN_INIT(&pool->lock);
+		HA_SPIN_INIT(&pool->lock);
 #endif
+	}
+	pool->users++;
 	return pool;
 }