Merge branch 'mj/gitweb-unreadable-config-error'

When given an existing but unreadable file as a configuration file,
gitweb behaved as if the file did not exist at all, but now it
errors out.  This is a change that may break backward compatibility.

* mj/gitweb-unreadable-config-error:
  gitweb: die when a configuration file cannot be read

gitweb/gitweb.perl

@@ -728,9 +728,11 @@ sub filter_and_validate_refs {
 sub read_config_file {
 	my $filename = shift;
 	return unless defined $filename;
-	# die if there are errors parsing config file
 	if (-e $filename) {
 		do $filename;
+		# die if there is a problem accessing the file
+		die $! if $!;
+		# die if there are errors parsing config file
 		die $@ if $@;
 		return 1;
 	}