qmp: unbreak build for non-vnc configuration

Signed-off-by: Leon Yu <chianglungyu@gmail.com>
Message-id: 1422853731-5282-1-git-send-email-chianglungyu@gmail.com
Fixes: df887684603a ("monitor: add query-vnc-servers command")
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
diff --git a/qmp.c b/qmp.c
index 20a9e97..6b2c4be 100644
--- a/qmp.c
+++ b/qmp.c
@@ -134,6 +134,12 @@
     error_set(errp, QERR_FEATURE_DISABLED, "vnc");
     return NULL;
 };
+
+VncInfo2List *qmp_query_vnc_servers(Error **errp)
+{
+    error_set(errp, QERR_FEATURE_DISABLED, "vnc");
+    return NULL;
+};
 #endif
 
 #ifndef CONFIG_SPICE