Make sh2ju not print 'error: 0' lines.

They cause false positives on Gubernator when it's looking for error
reasons.

third_party/forked/shell2junit/sh2ju.sh

@@ -113,7 +113,7 @@ function juLog() {
       H=`echo "$out" | egrep $icase "$ereg"`
       [ -n "$H" ] && err=1
   fi
-  echo "+++ error: $err"         | tee -a $outf
+  [ $err != 0 ] && echo "+++ error: $err"         | tee -a $outf
   rm -f $outf
 
   errMsg=`cat $errf`
@@ -174,4 +174,4 @@ EOF
 EOF
   fi
 
-}
+}