Cleanup default file locations and XenServer packaging

Cleanup default file locations and XenServer packaging

This commit cleans up the locations of a number of files and directories
used.  These include:

    - Config file lives in /etc/openvswitch/conf.db
    - Logs go into /var/log/openvswitch
    - ovsdb-server socket is /var/run/openvswitch/db.sock
    - Schema goes into /usr/share/openvswitch/vswitch.ovsschema
    - PID files go in /var/run/openvswitch

For XenServer, these additional changes are made:

    - Cores go in /var/xen/openvswitch
    - OVS binaries run in /var/xen/openvswitch

In addition, it attempts to cleanup the XenServer packaging.  This
includes referring to the project as "openvswitch" as opposed to the
somewhat presumptuous "vswitch".

Note: Changes to the Debian packaging will be forthcoming.