Merge 1610813 from trunk:

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

Submitted by: jailletc36
Reviewed by: jailletc36, ylavic, rjung
Backported by: jailletc36

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1632440 13f79535-47bb-0310-9956-ffa450edef68