Add CEPH_ARGS at the end of sys.argv

This allows, for instance, to pass a different client name to ceph by
exporting CEPH_ARGS="--id client_id".

Signed-off-by: Benoît Knecht <benoit.knecht@fsfe.org>
Signed-off-by: Sage Weil <sage@inktank.com>
Revert "ceph: parse CEPH_ARGS environment variable"

This reverts commit 67a95b9880c9bc6e858150352318d68d64ed74ad.

We now put CEPH_ARGS in the actual args we parse in python, which are passed
to rados piecemeal later.  This lets you put things like --id ... in there
that need to be parsed before librados is initialized.