Removing unnecessary includes that my IDE likes to sneak in.
No functional change.

* subversion/libsvn_repos/authz_pool.c
  (): Remove unnecessary apr_poll.h #include.

* subversion/tests/libsvn_subr/packed-data-test.c
  (): Remove unnecessary apr_poll.h #include.

git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1554621 13f79535-47bb-0310-9956-ffa450edef68