Fix improper check of errors when getting a suitable RandR mode.


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4940 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/unix/xserver/hw/vnc/XserverDesktop.cc b/unix/xserver/hw/vnc/XserverDesktop.cc
index 99fca44..7e068b1 100644
--- a/unix/xserver/hw/vnc/XserverDesktop.cc
+++ b/unix/xserver/hw/vnc/XserverDesktop.cc
@@ -946,7 +946,7 @@
     else {
       mode = findRandRMode(output, iter->dimensions.width(),
                            iter->dimensions.height());
-      if (!ret) {
+      if (mode == NULL) {
         vlog.error("Failed to find a suitable mode for %dx%d for output '%s'",
                    iter->dimensions.width(), iter->dimensions.height(),
                    output->name);
@@ -1027,7 +1027,7 @@
 
     mode = findRandRMode(output, iter->dimensions.width(),
                          iter->dimensions.height());
-    if (!ret) {
+    if (mode == NULL) {
       vlog.error("Failed to find a suitable mode for %dx%d for output '%s'",
                  iter->dimensions.width(), iter->dimensions.height(),
                  output->name);