Fix Perl warning in t/hook-inittab.t if /etc/inittab isn't present

aka "proper use of skip".

Fixes autopkgtest which failed due to STDERR output.

debian/changelog

@@ -4,6 +4,8 @@ xen-tools (4.6+dev-1) UNRELEASED; urgency=medium
     + Declare GitHub as primary hosting.
     + Integrate BUGS.markdown into README.markdown, move remaining
       contents of KNOWN_BUGS.markdown to the GitHub issue tracker.
+    + Fix Perl warning in t/hook-inittab.t if /etc/inittab isn't present.
+      - Fixes failed autopkgtest.
   * Update Vcs-* headers to point to GitHub instead of GitLab.
 
  -- Axel Beckert <abe@debian.org>  Tue, 21 Jul 2015 12:04:41 +0200

t/hook-inittab.t

@@ -16,14 +16,12 @@ my $hook_dir = $ENV{AS_INSTALLED_TESTING} ? '/usr/share/xen-tools' : 'hooks';
 #
 #  Check if build system has /etc/inittab.
 #
-SKIP: {
-    skip '/etc/inittab not present' unless -e "/etc/inittab";
-
-#
-#  Rather than having a hardwired list of distributions to test
-# against we look for subdirectories beneath hooks/ and test each
-# one.
-#
+if (-e "/etc/inittab") {
+    #
+    #  Rather than having a hardwired list of distributions to test
+    # against we look for subdirectories beneath hooks/ and test each
+    # one.
+    #
     foreach my $dir ( glob( "$hook_dir/*" ) )
     {
         next if ( $dir =~ /CVS/i );
@@ -39,8 +37,9 @@ SKIP: {
             testHook( $dist );
         }
     }
-} # SKIP
-
+} else {
+    plan skip_all => '/etc/inittab not present';
+}
 
 done_testing();