Stick with alternative cache location.
Stick with alternative cache location.

Here's the story:

- When we validate an incoming message, we try to check that it is signed with
  our CA and that it is not in our CRL.
- When we do that, we check our local cache of those files.  If they are too
  old, we grab them fresh from ``https://fedoraproject.org/fedmsg/{crl,ca}.pem``.
- We try to write them to ``/var/cache/fedmsg/foo`` first.  If we don't have
  rights to write there, we try to write them instead to ``~/.local/var/cache/fedmsg/foo``.
- When the *next* message comes in, we try to check if
  ``/var/cache/fedmsg/foo`` is too old.. *but it doesn't exist*.  We wrote it
  to ``~/.local/var/cache/fedmsg/foo`` last time.
- We end up pulling down the CRL and the CA cert *every time* for *every
  message* if we don't have write access to ``/var/cache/fedmsg/``.

This fixes that so that if we find the certs in
``~/.local/var/cache/fedmsg/foo``.. we'll just re-use those (this is the way it
was supposed to work all along).

vivekanand1101/fedmsg,chaiku/fedmsg,fedora-infra/fedmsg,pombredanne/fedmsg,maxamillion/fedmsg,vivekanand1101/fedmsg,vivekanand1101/fedmsg,pombredanne/fedmsg,maxamillion/fedmsg,pombredanne/fedmsg,maxamillion/fedmsg,fedora-infra/fedmsg,chaiku/fedmsg,chaiku/fedmsg,fedora-infra/fedmsg