When using the routes mapper's collection to map from URLs to
python functions several additional URIs are created by
default: 'new', 'format' and 'edit', eg this URI
/v1/images/new
was accessible and would return a '500'.
/v1/images/detail.xxx
was accessible and a 'GET' to it would create a file called 'detail.xxx'
in the image cache directory (where 'xxx' is an arbitrary string).
Similar resources for image memberships existed.
Other collection URIs (for both the API and Registry) would return
unexpected behaviour.
Use explicit mappings rather than a 'collection' to remove
the superfluous resources.
Fixes bug 1185828.
Change-Id: I2f451f0208d43cdc83dcf58a41ea31359b18fcf2