Update krecord to support nginx-rtmp

fixes COMMS-1731

Test plan:
- Test media recorder against FMS: it should work
- Test media recorder against nginx-rtmp: it should work
- Make sure audio-only and video work
- Make sure recordings > 1min work
- Maks sure seeking, stopping, and playing the recording multiple times works

Change-Id: Icaa5897e23c7330f49623fecdef6e05935e2a0c0
Reviewed-on: https://gerrit.instructure.com/170842
Tested-by: Jenkins
Reviewed-by: Steven Burnett <sburnett@instructure.com>
QA-Review: KC Naegle <knaegle@instructure.com>
Product-Review: Steven Burnett <sburnett@instructure.com>

public/javascripts/media_comments.js

@@ -342,7 +342,8 @@ import 'jqueryui/tabs'
           partnerData: $.mediaComment.partnerData(),
           partner_data: $.mediaComment.partnerData(),
           entryName:temporaryName,
-          soundcodec: 'Speex'
+          soundcodec: 'Speex',
+          autoPreview: '0'
         };
 
         var params = {