Ignore Range requests

We're seeing elevated 503s due to Varnish range request handling
in combination with gzip/gunzip support. Because Varnish receives
most objects from the backend(s) compressed, it needs to gunzip
and gzip to serve a response, which appears to be failing often
in various ways.

Until we have time to debug this properly, let's disable Range
requests for the Text cluster, as they're not tremendously
helpful anyway.

Change-Id: I2524a8d9ca1006da26bae174d6067e6e71d50c37
Merge "Ignore Range requests" into production