merge from trunk:

  *) mod_cache: Eliminate a bogus error in the log when a filter returns
     AP_FILTER_ERROR. [Niklas Edmundsson <nikke acc.umu.se>]

Reviewed by: minfrin, wrowe, trawick
  


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.2.x@483974 13f79535-47bb-0310-9956-ffa450edef68