[backend] fix fatal errors not failing sign jobs

Do not check the 'result' element, as it is set by the repo server.
Also make the error message appended to the log file more
informative.

src/backend/bs_signer

@@ -932,7 +932,7 @@ sub signjob {
 	$error = "Need an RSA key for openssl signing, please create a new key\n";
 	$jobstatus->{'result'} = 'failed';
       }
-      $jobstatus->{'result'} = 'failed' if !$jobstatus->{'result'} && $error =~ s/^fatal: //;
+      $jobstatus->{'result'} = 'failed' if $error =~ s/^fatal: //;
       if ($jobstatus->{'result'} && $jobstatus->{'result'} eq 'rebuild') {
         warn("rebuilding: $error\n");
 	if ($info->{'followupfile'}) {
@@ -948,7 +948,7 @@ sub signjob {
       }
       if ($jobstatus->{'result'} && $jobstatus->{'result'} eq 'failed') {
         warn("failed: $error\n");
-	BSUtil::appendstr("$jobdir/logfile", "\n\n$error");
+	BSUtil::appendstr("$jobdir/logfile", "\n\nsigning failed: $error");
 	$jobstatus->{'code'} = 'finished';
 	writexml("$jobsdir/$arch/.$job:status", "$jobsdir/$arch/$job:status", $jobstatus, $BSXML::jobstatus);
 	updateredisjobstatus($arch, $job, $info, 'finished');