Avoid loading Patch object in /cat/ servlet

We don't actually need the Patch object, we only used it to obtain
the file name, but the key we used to locate the Patch object has
the file name embedded as part of it.

Change-Id: I9a0a6928de438ab80af0577c20538ae47818f1ed
Signed-off-by: Shawn O. Pearce <sop@google.com>
2 files changed