Item12367: preserve name encoding symmetry in uploads in cached requests

Since the filename for a cached upload is based on the URL-encoded version of
the original filename, we need to use the URL-encoded version when applying
the cached upload, too.

Original Author: JanKrueger <JanKrueger@0b4bb1d4-4e5a-0410-9cc4-b2b747904278>

git-svn-id: http://svn.foswiki.org/branches/Release01x01/core@16464 0b4bb1d4-4e5a-0410-9cc4-b2b747904278