Revert "Don't run the default vcl_fetch function on mobile caches"

This reverts commit e51d71c39635a9e8f74468de6d9527edfeb5e007.

Change-Id: Ie31af948585361f8583d54b53486b24f97644c3e
Merge "Revert "Don't run the default vcl_fetch function on mobile caches"" into production