slirp: Fix typo in net_slirp_hostfwd_remove

Report an error when err is nonzero, not when it is zero.

Signed-off-by: Geoffrey Thomas <geofft@ldpreload.com>
Signed-off-by: Stefan Hajnoczi <stefanha@linux.vnet.ibm.com>
diff --git a/net/slirp.c b/net/slirp.c
index 6646ecb..18e07ba 100644
--- a/net/slirp.c
+++ b/net/slirp.c
@@ -351,7 +351,7 @@
                                host_addr, host_port);
 
     monitor_printf(mon, "host forwarding rule for %s %s\n", src_str,
-                   err ? "removed" : "not found");
+                   err ? "not found" : "removed");
     return;
 
  fail_syntax: