1) fixes possible NULL pointer reference w/NoCache

2) fixes NoCache behavior when using ProxyRemote (ProxyRemote host would
     cache nothing if it was in the local domain, and the local domain
     was in the NoCache list)
3) Adds Host: header when not available
4) Some code cleanup and clarification

1) and 2) were reported by Martin Kraemer, with patches. The function,
though not the form, of Martin's stuff is adhered to here.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@77244 13f79535-47bb-0310-9956-ffa450edef68