Update p5-Apache2-AuthCookie to 3.18.

Changes from previous:
----------------------
3.18  2011-01-24
   - remove 3.17's test skip hacks, and bump Apache::Test prerequisite to v1.35
     which fixes this issue.
   - fix MANIFEST.SKIP to ignore generated t/conf/mime.types
   - remove dist.ini, weaver.ini from dists
   - fixed t/real.t to use correct -withtestmore import syntax
   - rename sample authcookie handlers to Sample::Apache and Sample::Apache2
     namespaces

3.17  2011-01-19
   - skip the test suite if running as root.  Apache::Test 1.34 fails the test
     suite if running as root instead of skipping it.  By skipping, AuthCookie can
     be installed via CPAN.pm as root.

3.16  2011-01-19
   - require Apache::Test 1.32 - fixes ubuntu build issue
   - remove mod_perl/mod_perl2 related prereq's from META.yml.  The correct mod
     perl version is not known until Makefile.PL is run.  CPAN.pm should not
     try to install either one until it is known which one is appropriate.
     (RT 64926)

3.15  2010-08-27
   - enable Dist::Zilla Manifest plugin
   - add FAQ
   - add FAQ entry on how to protect an entire site/document root
   - recognize_user: return DECLINED if user is already set
   - refactor P3P header generation into send_p3p($r) so subclasses can overload it

3.14  2010-04-12
   - MP2: doc updates: remove beta warnings, change Apache::AuthCookie to
     Apache2::Authcookie where appopriate.
   - docs: change my email to my cpan address
   - docs: remove POST limitations reference (handled by POST to GET conversion)
   - sign dist with Module::Signature
   - add signature test
   - MP1: perltidy Apache::AuthCookie sources.
   - update mod_perl2 prereq version (still 2.0.0 RC5, but version number was
     incorrect in Makefile.PL)
   - use Dist::Zilla for building the dist


(hiramatsu)