hw/xwin: Mitigate a race condition in clipboard thread initialization

Remove the variables g_fClipboardLaunched and g_fClipboardStarted from
winInitializeGlobals(), as their re-initialization is handled in the
file hw/xwin/InitOutput.c.

Re-initializing g_fClipboardLaunched and g_fClipboardStarted during
the server reset procedure can lead to the clipboard thread being
launched two times and sometimes leads to a crash of the X server...

Reviewed-by: Jon TURNEY <jon.turney@dronecode.org.uk>
Reviewed-by: Colin Harrison <colin.harrison@virgin.net>

hw/xwin/winglobals.c

@@ -114,8 +114,6 @@ winInitializeGlobals (void)
 {
   g_dwCurrentThreadID = GetCurrentThreadId ();
 #ifdef XWIN_CLIPBOARD
-  g_fClipboardLaunched = FALSE;
-  g_fClipboardStarted = FALSE;
   g_iClipboardWindow = None;
   g_pClipboardDisplay = NULL;
   g_atomLastOwnedSelection = None;