Clean up header guards that don't match their file name

Header guard symbols should match their file name to make guard
collisions less likely.  Offenders found with
scripts/clean-header-guards.pl -vn.

Cleaned up with scripts/clean-header-guards.pl, followed by some
renaming of new guard symbols picked by the script to better ones.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
diff --git a/qga/vss-win32/vss-common.h b/qga/vss-win32/vss-common.h
index 1ffde0f..c81a856 100644
--- a/qga/vss-win32/vss-common.h
+++ b/qga/vss-win32/vss-common.h
@@ -10,8 +10,8 @@
  * See the COPYING file in the top-level directory.
  */
 
-#ifndef VSS_WIN32_H
-#define VSS_WIN32_H
+#ifndef VSS_COMMON_H
+#define VSS_COMMON_H
 
 #define __MIDL_user_allocate_free_DEFINED__
 #include <windows.h>