Make debug logging consistent in forwarder and cache servlet

In the forwarder, change "evict" to "invalidate" to match the wording
used in the servlet.

In the servlet, update the log format to include the key that was
invalidated, to make it match the formatting of the forwarder's log.

Change-Id: I5e5741083e6b06c3b0fa5f2cf54ce16f0827aebf
2 files changed