Clean up ill-advised or unusual header guards

Cleaned up with scripts/clean-header-guards.pl.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Richard Henderson <rth@twiddle.net>
diff --git a/include/io/channel-watch.h b/include/io/channel-watch.h
index 76d7642..63bc4ae 100644
--- a/include/io/channel-watch.h
+++ b/include/io/channel-watch.h
@@ -18,8 +18,8 @@
  *
  */
 
-#ifndef QIO_CHANNEL_WATCH_H__
-#define QIO_CHANNEL_WATCH_H__
+#ifndef QIO_CHANNEL_WATCH_H
+#define QIO_CHANNEL_WATCH_H
 
 #include "io/channel.h"
 
@@ -87,4 +87,4 @@
                                           int fdwrite,
                                           GIOCondition condition);
 
-#endif /* QIO_CHANNEL_WATCH_H__ */
+#endif /* QIO_CHANNEL_WATCH_H */