Fixing Indirector::Facts::Couch loading

It was previously failing to load at all if couch was missing,
but now it only fails on initialization.

This means that you can tell that the terminus is there when
you're missing couch, but you just can't use it.

Signed-off-by: Luke Kanies <luke@puppetlabs.com>
Reviewed-by: Daniel Pittman <daniel@puppetlabs.com>