Fixes a case on chunked cached objects, 304s and Ranges
Fixes a case on chunked cached objects, 304s and Ranges

Before this fix, in the deranged case of

       1. Chunked object in cache (which is a static asset)
       2. Object goes stale
       3. Client does a Range request
       4. Origin responds with a 304

we can serve a "200 OK" with a partial object (the requested range). This
not only messes up a client, but in the parent proxy setup, can pollute the
downstream cache with a truncated object.

This fixes #3409.

SolidWallOfCode/trafficserver,pbchou/trafficserver,dyrock/trafficserver,davidbz/trafficserver,vmamidi/trafficserver,bryancall/trafficserver,SolidWallOfCode/trafficserver,vmamidi/trafficserver,duke8253/trafficserver,chitianhao/trafficserver,bryancall/trafficserver,persiaAziz/trafficserver,pbchou/trafficserver,persiaAziz/trafficserver,pbchou/trafficserver,duke8253/trafficserver,chitianhao/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,davidbz/trafficserver,pbchou/trafficserver,duke8253/trafficserver,bryancall/trafficserver,dyrock/trafficserver,persiaAziz/trafficserver,dyrock/trafficserver,duke8253/trafficserver,bryancall/trafficserver,vmamidi/trafficserver,persiaAziz/trafficserver,chitianhao/trafficserver,dyrock/trafficserver,dyrock/trafficserver,vmamidi/trafficserver,vmamidi/trafficserver,SolidWallOfCode/trafficserver,bryancall/trafficserver,bryancall/trafficserver,persiaAziz/trafficserver,duke8253/trafficserver,persiaAziz/trafficserver,SolidWallOfCode/trafficserver,chitianhao/trafficserver,davidbz/trafficserver,chitianhao/trafficserver,davidbz/trafficserver,persiaAziz/trafficserver,vmamidi/trafficserver,duke8253/trafficserver,davidbz/trafficserver,chitianhao/trafficserver,chitianhao/trafficserver,SolidWallOfCode/trafficserver,davidbz/trafficserver,SolidWallOfCode/trafficserver,duke8253/trafficserver,dyrock/trafficserver,pbchou/trafficserver,SolidWallOfCode/trafficserver,pbchou/trafficserver