Dpkg::Arch: Properly fix debarch_to_debtriplet() callers

The previous checks have always been shady (the subsequent fix too),
as they didn't guarantee what they were checking for, i.e. that the
array was not missing an element. Now that debarch_to_debtriplet()
returns better values, just check for the correct array size (to be
future-proof), instead of checking for the array not being empty, or
for undefined elements (something that should never happen anymore).

scripts/Dpkg/Arch.pm

@@ -1,4 +1,4 @@
-# Copyright © 2006-2012 Guillem Jover <guillem@debian.org>
+# Copyright © 2006-2013 Guillem Jover <guillem@debian.org>
 #
 # This program is free software; you can redistribute it and/or modify
 # it under the terms of the GNU General Public License as published by
@@ -399,7 +399,7 @@ sub debarch_eq($$)
     my @a = debarch_to_debtriplet($a);
     my @b = debarch_to_debtriplet($b);
 
-    return 0 if grep(!defined, (@a, @b)) or !scalar(@a) or !scalar(@b);
+    return 0 if scalar @a != 3 or scalar @b != 3;
 
     return ($a[0] eq $b[0] && $a[1] eq $b[1] && $a[2] eq $b[2]);
 }
@@ -413,7 +413,7 @@ sub debarch_is($$)
     my @real = debarch_to_debtriplet($real);
     my @alias = debwildcard_to_debtriplet($alias);
 
-    return 0 if grep(!defined, (@real, @alias)) or !scalar(@real) or !scalar(@alias);
+    return 0 if scalar @real != 3 or scalar @alias != 3;
 
     if (($alias[0] eq $real[0] || $alias[0] eq 'any') &&
         ($alias[1] eq $real[1] || $alias[1] eq 'any') &&
@@ -432,7 +432,7 @@ sub debarch_is_wildcard($)
 
     my @triplet = debwildcard_to_debtriplet($arch);
 
-    return 0 unless defined $triplet[0];
+    return 0 if scalar @triplet != 3;
     return 1 if (grep { $_ eq 'any' } @triplet);
     return 0;
 }