Make XSLoader's UPSTREAM as undef

The upstream is supposed to be "blead", but the CPAN version of
XSLoader 0.16 and the one that has shipped with perl 5.17.3 are
different (doc changes only). The problem (cmp_version.t failing)
should disappear after the next perl release.

diff --git a/Porting/Maintainers.pl b/Porting/Maintainers.pl
index a422184..a228103 100755 (executable)
--- a/Porting/Maintainers.pl
+++ b/Porting/Maintainers.pl
@@ -2132,7 +2132,8 @@ use File::Glob qw(:case);
                 ),
             'XSLoader.pm',    # we use XSLoader_pm.PL
         ],
-        'UPSTREAM' => 'blead',
+        # Revert UPSTREAM to 'blead' after 0.17 is released
+        'UPSTREAM' => undef,
     },
 
     's2p' => {