fix logic in ap_method_list_(add|remove) in order:
       - to correctly reset bits
       - not to modify the 'method_mask' bitfield unnecessarily

Also remove a useless 'register' in the declaration of a variable.

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1610813 13f79535-47bb-0310-9956-ffa450edef68
  *) SECURITY: CVE-2013-5704 (cve.mitre.org)
     core: HTTP trailers could be used to replace HTTP headers
     late during request processing, potentially undoing or
     otherwise confusing modules that examined or modified
     request headers earlier.  Adds "MergeTrailers" directive to restore
     legacy behavior.  

Submitted By: Edward Lu, Yann Ylavic, Joe Orton, Eric Covener
Committed By: covener



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1610814 13f79535-47bb-0310-9956-ffa450edef68