Revert "Fix issue with memcached keys being too large."

This reverts commit ae7c428d4d355c2270d5139acebe464b925a00a5.
Revert "Fix bug 1054472: Use ETags to determine if we can send 304s."

This reverts commit b12f537e8f9b1de80dcc86d0814222d8cd595887.
Fix bug 1054472: Add ETag header to responses.