Extract the httpd version at configure time rather than in
davautocheck.sh, pass --httpd-version as a testsuite option
rather than using the environment SVNTEST_HTTPD_VERSION.
This is how other test flags support both 'make check' and
'make davautocheck'.

* subversion/tests/cmdline/davautocheck.sh
  (SVNTEST_HTTPD_VERSION): Move code to apache.m4.

* build/ac-macros/apache.m4
  (HTTPD_VERSION): Set value, based on code from davautocheck.sh.

* Makefile.in
  (check): Pass --httpd-version.

* build/run_tests.py
  (TestHarness.__init__, TestHarness._run_py_test, main): Add httpd_version.

* subversion/tests/cmdline/svntest/main.py
  (is_mod_dav_url_quoting_broken): Use option rather than environment.
  (TestSpawningThread.run_one): Handle --httpd-version.
  (_create_parser): Add --httpd-version. 


git-svn-id: https://svn.apache.org/repos/asf/subversion/trunk@1639634 13f79535-47bb-0310-9956-ffa450edef68