Pass return code to caller in mlx4_close_xrc_domain.

ibv_cmd_close_xrc_domain() can return a busy or invalid error code.
Need to pass this upward to caller.
(Bugzilla 999)

Signed-off-by: Jack Morgenstein <jackm@dev.mellanox.co.il>

Index: libmlx4/src/verbs.c
===================================================================
--- libmlx4.orig/src/verbs.c	2008-09-01 10:51:11.000000000 +0300
+++ libmlx4/src/verbs.c	2008-09-01 10:52:40.000000000 +0300
@@ -774,9 +774,11 @@
 
 int mlx4_close_xrc_domain(struct ibv_xrc_domain *d)
 {
-	ibv_cmd_close_xrc_domain(d);
-	free(d);
-	return 0;
+	int ret;
+	ret = ibv_cmd_close_xrc_domain(d);
+	if (!ret)
+		free(d);
+	return ret;
 }
 
 int mlx4_create_xrc_rcv_qp(struct ibv_qp_init_attr *init_attr,