Non-standard method in bad request can cause crash

Fix is to check for a normal sort of method (that would actually need a cache lookup) in HttpTransact::HandleCacheOpenReadMiss() to do

     s->cache_info.action = CACHE_DO_NO_ACTION;

instead of

     s->cache_info.action = CACHE_PREPARE_TO_WRITE;

for anything weird. But I am concerned that this might cause problems if someone wants to add support for a weird method...but maybe that never works right with the cache anyway...