Fix photologue cache path test
Fix photologue cache path test

ImageModel.cache_path returns an absolute path.  If we don't specify an
abspath for PHOTOLOGUE_DIR in the settings, PHOTOLOGUE_DIR defaults to a
relative path (just "photologue") which we use as a basis to check the
return value of ImageModel.cache_path, causing the test to fail.

amarandon/pinax,amarandon/pinax,amarandon/pinax,amarandon/pinax