Fix the error cases in the cache_select() loop. On error we must loop around

to the next provider, not return DECLINED too early, except for the
revalidate case, where returning DECLINED is correct behaviour.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1023392 13f79535-47bb-0310-9956-ffa450edef68