Replace the usage of 'manager' with 'os_primary'

In tempest, alias 'manager' has been moved to 'os_primary'
in version Pike, and it will be removed in version Queens [1].

The other usages which also need to be replaced, are listed below:
* admin_manager > os_admin [2]
* os_adm > os_admin [3]
* os > os_primary [4]

[1] https://review.openstack.org/#/c/468036/
[2] https://review.openstack.org/#/c/467852/
[3] https://review.openstack.org/#/c/467605/
[4] https://review.openstack.org/#/c/466991/

Change-Id: I295bc37b903ada341320b73de6ebb4bf31aa955b
3 files changed