http-push: add regression tests
http-push tests require a web server with WebDAV support.
This commit introduces a HTTPD test library, which can be configured using
the following environment variables.
GIT_TEST_HTTPD enable HTTPD tests
LIB_HTTPD_PATH web server path
LIB_HTTPD_MODULE_PATH web server modules path
LIB_HTTPD_PORT listening port
LIB_HTTPD_DAV enable DAV
LIB_HTTPD_SVN enable SVN
LIB_HTTPD_SSL enable SSL
Signed-off-by: Clemens Buchacher <drizzd@aon.at>
Signed-off-by: Junio C Hamano <gitster@pobox.com>