Merge r1756843, r1897890, r1898731, r1900064, r1900077 from trunk

Merge r1756843, r1897890, r1898731, r1900064, r1900077 from trunk

   * mod_auth_digest: Fix some missed "strcasecmp <--> ap_cstr_casecmp" conversions
   * mod_dav: fix a typo
   * mod_lua: Avoid "may be uninitialized" warning
   * ab: Fix alignment in an 'if' block.
   * mod_authz_dbd: fix select-groups example, bz 66010

Submitted by: jailletc36, rpluem, rpluem, jailletc36, gbechis
Reviewed by: jailletc36, ylavic, rpluem
Backported by: jailletc36

git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1901567 13f79535-47bb-0310-9956-ffa450edef68