Improve the error condition encountered when trying to use a DAV write-through proxy but not having mod_proxy loaded. See this email thread: <http://subversion.tigris.org/ds/viewMessage.do?dsForumId=462&dsMessageId=2412741>.
Improve the error condition encountered when trying to use a DAV
write-through proxy but not having mod_proxy loaded. See this email thread:
<http://subversion.tigris.org/ds/viewMessage.do?dsForumId=462&dsMessageId=2412741>.

In mod_dav_svn, when processing an SVNMasterURI directive, check that
mod_proxy is available in the httpd runtime.  Forwarding writes to a master
from a slave requires the mod_proxy handler, and when it isn't present, the
failure is ugly & opaque.  Apache's core, default handler sends back a "405
Not Allowed," for non-GET which looks like an authz failure.

BTW, there's precedent for using ap_find_linked_module() to check that
module dependencies are present.  Namely, mod_rewrite looks for mod_proxy,
and mod_authnz_ldap looks for util_ldap.

* subversion/mod_dav_svn/mod_dav_svn.c
  (SVNMasterURI_cmd): Use ap_find_linked_module() to ensure that mod_proxy
    is available.

Patch by: Dave Brown <dave.brown{_AT_}wandisco.com>

jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion,jmckaskill/subversion