ceph-rest-api: clean up options/environment

ceph-rest-api:
* create app from wrapper by calling generate_app()
* pass args to generate_app() (early parsed in wrapper)
* parse -i/--id here as well
* set addr:port on returned app object
* handle only EnvironmentError exceptions; let others spew traceback
* turn off debug when running singlethreaded server

ceph_rest_api.py:
* put glob.* on app.ceph_* instead; pass around app in init code
* drop conf parsing (let librados do its job)

Documentation updated to match.

Signed-off-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>
rados.py: missing parameter to make_ex()

Signed-off-by: Dan Mick <dan.mick@inktank.com>
Reviewed-by: Sage Weil <sage@inktank.com>