[Bugfix] Set pvfb->pixelFormatDefined only if format is defined.


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@4126 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/unix/xserver/hw/vnc/xvnc.cc b/unix/xserver/hw/vnc/xvnc.cc
index d5bffbe..5ce6163 100644
--- a/unix/xserver/hw/vnc/xvnc.cc
+++ b/unix/xserver/hw/vnc/xvnc.cc
@@ -1204,15 +1204,15 @@
     pScreen->whitePixel = pvfb->whitePixel;
 
     if (!pvfb->pixelFormatDefined) {
-	pvfb->pixelFormatDefined = TRUE;
-
 	switch (pvfb->fb.depth) {
 	case 16:
+	    pvfb->pixelFormatDefined = TRUE;
 	    pvfb->rgbNotBgr = TRUE;
 	    pvfb->blueBits = pvfb->redBits = 5;
 	    pvfb->greenBits = 6;
 	    break;
 	case 32:
+	    pvfb->pixelFormatDefined = TRUE;
 	    pvfb->rgbNotBgr = TRUE;
 	    pvfb->blueBits = pvfb->redBits = pvfb->greenBits = 8;
 	    break;