Fatal error for empty action file

- Issue error if a file with the name of the action exists on the
  CONFIG_PATH

Signed-off-by: Tom Eastep <teastep@shorewall.net>

Shorewall/Perl/Shorewall/Rules.pm

@@ -2082,6 +2082,12 @@ sub process_action(\$\$$) {
 
     pop_open;
 
+    unless ( @{$chainref->{rules}} ) {
+	my $file = find_file( $action );
+
+	fatal_error "File action.${action} is empty and file $action exists - the two must be combined as described in the Migration Considerations section of the Shorewall release notes" if -f $file;
+    }
+
     #
     # Pop the action parameters
     #