Fix hacking check for jsonutils

Hacking checks with logical_lines should use yield not return.

The jsonutils rule was added in:
I86ed6cd3316dd4da5e1b10b36a3ddba3739316d3

Now that the function uses yield, it can trigger twice in dumps (dump
and dump), so look for a '(' at the afterwards. Don't display the '(' at
the end of the error message since its confusing to read.

Change-Id: I277dba08fdd30734409eee36008cebda35886968
Closes-Bug: #1356687
Merge "Fix hacking check for jsonutils"