Merge ch_computescheduler.xml to computescheduler.xml

As a first step in resolving bug 1212862 which states that
/openstack-compute-admin/computescheduler.xml and
/openstack-config/ch_computescheduler.xml should have the same
content, I'll merge all changes done to ch_computescheduler.xml to
computescheduler.xml.

This patch merges the following commits:
    clean-up of 'common' dir in openstack-manuals (remove unused files
and use common naming convention)
    Change-Id: I3e0f03ac42c39a2ed3fed2d530beb61f6b81873c
----
    Adds link to block storage page from config and admin scheduler
pages. Also fixes missed update to admin scheduler page from
bug-1192627,
    Change-Id: Ie33d039a3f668215d32e18edb8b5b3bea71b9aa6
----
    bug 1188522, author sean roberts, removed reference to volume
scheduler in ch_computescheduler.xml

    Change-Id: Ie26b1b8814a169e79ebbdcbde8579e5aa820a823
----

Change-Id: I668a7c54c7e237b3989e44b6745e940d080abbfe
Partial-Bug: #1212862
Merge "Merge ch_computescheduler.xml to computescheduler.xml"