Fix options and their groups - etc/glance-api.conf

As per the docs at [0] , some of the options should have been moved
around in the etc/glance-api.conf. This patch changes the conf file to:

    1. indicate new default values
    2. change the group of some of the configs in order to adhere to
       new groups as expected by the deployer.
    3. deprecated configs have been removed or replaced with new ones.

[0] http://docs.openstack.org/trunk/config-reference/content/glance-conf-changes-master.html

Fixes bug: 1380689

Change-Id: I5b5ab96b050b502007e6660a7a613e252404d4e8
Merge "Fix options and their groups - etc/glance-api.conf" into proposed/juno