No DID in CDR on incoming Google Voice Calls, added the fix but now get security (tampered file) warning

I noticed that on my system, when I view CDR reports no DID is reported on incoming calls on Google Voice trunks. I fixed this by going into /var/www/html/admin/modules/motif/functions.inc.php and adding a line, but now FreePBX is warning me that I have a tampered file. After the line that reads:

{noformat}
$ext->add($incontext, $address, '', new ext_setvar('CALLERID(name)', '${CALLERID(name):1}'));{noformat}

I added this:

{noformat}
$ext->add($incontext, $address, '', new ext_setvar('CDR(did)', $list['phonenum']));{noformat}

That fixes the problem, and once you reload the configuration the DID appears properly on new incoming GV calls. But now I get a security warning that I have a tampered file whenever I log into FreePBX, so I was hoping maybe this fix could be put into the distribution version of the Google Voice (Motif) module so the warning will go away.

(Added later) I need to clarify one thing about this issue. It appears that some incoming Google Voice calls were getting the DID correctly set, and some were not. it appears that if the call gets as far as one of the [ext-did-000?] contexts then the DID does get set. However if the call gets diverted before then, it does not. Where this is particularly noticeable is if the call winds up being blacklisted. You can see that the call came in, but you have no idea what DID it came in on. The added line assures that the DID is set practically as soon as the call arrives, so you have fewer blank DID entries in the CDR.

I originally reported this on the forum at http://community.freepbx.org/t/i-fixed-a-problem-no-did-in-cdr-for-incoming-google-voice-and-now-freepbx-is-warning-me-about-the-tampered-module/29021 and was asked to post a bug report.