Fix assorted inconsistent function declarations.

While gcc doesn't complain if you declare a function "static" and then
define it not-static, other compilers do; and in any case the code is
highly misleading this way.  Add the missing "static" keywords to a
couple of recent patches.  Per buildfarm member pademelon.

contrib/pg_upgrade/pg_upgrade.c

@@ -259,7 +259,7 @@ CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, const char
 }
 #endif
 
-void
+static void
 get_restricted_token(const char *progname)
 {
 #ifdef WIN32

src/bin/pg_resetxlog/pg_resetxlog.c

@@ -1149,7 +1149,7 @@ CreateRestrictedProcess(char *cmd, PROCESS_INFORMATION *processInfo, const char
 }
 #endif
 
-void
+static void
 get_restricted_token(const char *progname)
 {
 #ifdef WIN32