don't show diff of sorted files

OBS-URL: https://build.opensuse.org/package/show/openSUSE:Tools/build-compare?expand=0&rev=119

same-build-result.sh

@@ -102,8 +102,7 @@ if test -e $OLDDIR/rpmlint.log -a -e $OTHERDIR/rpmlint.log; then
   sort -u $OTHERDIR/rpmlint.log|sed -e "s,$release2,@RELEASE@,g" -e "s|/tmp/rpmlint\..*spec|.spec|g"  > $file2
   if ! cmp -s $file1 $file2; then
     echo "rpmlint.log files differ:"
-    # File is sorted, so don't give context that will confuse readers
-    diff -u0 $file1 $file2 |head -n 20
+    diff -u $OLDDIR/rpmlint.log $OTHERDIR/rpmlint.log |head -n 20
     SUCCESS=0
   fi
   rm $file1 $file2