MINOR: connections: Add a flag to know if we're in the safe or idle list.

Add flags to connections, CO_FL_SAFE_LIST and CO_FL_IDLE_LIST, to let one
know we are in the safe list, or the idle list.
diff --git a/include/proto/server.h b/include/proto/server.h
index ca794ab..7ba9c83 100644
--- a/include/proto/server.h
+++ b/include/proto/server.h
@@ -262,6 +262,8 @@
 			return 0;
 		}
 		MT_LIST_DEL(&conn->list);
+		conn->flags = (conn->flags &~ CO_FL_LIST_MASK) |
+		              (is_safe ? CO_FL_SAFE_LIST : CO_FL_IDLE_LIST);
 		MT_LIST_ADDQ(is_safe ? &srv->safe_conns[tid] : &srv->idle_conns[tid],
 		             (struct mt_list *)&conn->list);
 		srv->curr_idle_thr[tid]++;
diff --git a/include/types/connection.h b/include/types/connection.h
index 32a8590..4f02895 100644
--- a/include/types/connection.h
+++ b/include/types/connection.h
@@ -140,6 +140,10 @@
 	CO_FL_NONE          = 0x00000000,  /* Just for initialization purposes */
 
 	/* Do not change these values without updating conn_*_poll_changes() ! */
+	CO_FL_SAFE_LIST     = 0x00000001,  /* 0 = not in any list, 1 = in safe_list  */
+	CO_FL_IDLE_LIST     = 0x00000002,  /* 2 = in idle_list, 3 = invalid */
+	CO_FL_LIST_MASK     = 0x00000003,  /* Is the connection in any server-managed list ? */
+
 	/* unused : 0x00000001 */
 	/* unused : 0x00000002 */
 	/* unused : 0x00000004, 0x00000008 */
diff --git a/src/backend.c b/src/backend.c
index b60e900..c868d93 100644
--- a/src/backend.c
+++ b/src/backend.c
@@ -1173,6 +1173,7 @@
 		if (srv_conn) {
 			reuse_orphan = 1;
 			reuse = 1;
+			srv_conn->flags &= ~CO_FL_LIST_MASK;
 		}
 	}