Initialize the local variable before refer to them.

git-svn-id: https://edk2.svn.sourceforge.net/svnroot/edk2/trunk/edk2@10577 6f19259b-4bc3-4df7-8a09-765794883524

EdkCompatibilityPkg/Foundation/Library/Dxe/Graphics/Print.c

@@ -188,6 +188,7 @@ Returns:
   //
   // For now, allocate an arbitrarily long buffer
   //
+  BufferLen = 0;
   Buffer = EfiLibAllocateZeroPool (0x10000);
   if (Buffer == NULL) {
     return 0;
@@ -428,14 +429,15 @@ Returns:
 
   Handle = gST->ConsoleOutHandle;
 
+  GraphicsOutput = NULL;
+  UgaDraw        = NULL;
   Status = gBS->HandleProtocol (
                   Handle,
                   &gEfiGraphicsOutputProtocolGuid,
                   (VOID**)&GraphicsOutput
                   );
 
-  UgaDraw = NULL;
-  if (EFI_ERROR (Status)) {
+  if (EFI_ERROR (Status) || (GraphicsOutput == NULL)) {
     GraphicsOutput = NULL;
 
     Status = gBS->HandleProtocol (