Run pg_upgrade and pg_resetxlog with restricted token on Windows

As with initdb these programs need to run with a restricted token, and
if they don't pg_upgrade will fail when run as a user with Adminstrator
privileges.

Backpatch to all live branches. On the development branch the code is
reorganized so that the restricted token code is now in a single
location. On the stable bramches a less invasive change is made by
simply copying the relevant code to pg_upgrade.c and pg_resetxlog.c.

Patches and bug report from Muhammad Asif Naeem, reviewed by Michael
Paquier, slightly edited by me.

contrib/pg_upgrade/pg_upgrade.c

@@ -37,6 +37,7 @@
 #include "postgres_fe.h"
 
 #include "pg_upgrade.h"
+#include "common/restricted_token.h"
 
 #ifdef HAVE_LANGINFO_H
 #include <langinfo.h>
@@ -75,6 +76,8 @@ main(int argc, char **argv)
 
 	parseCommandLine(argc, argv);
 
+	get_restricted_token(os_info.progname);
+
 	adjust_data_dir(&old_cluster);
 	adjust_data_dir(&new_cluster);