Summary: Document the procedure for TCP listening of libvirt on Ubuntu 12.04

Detail: This is now controlled by a variable in /etc/default/libvirt-bin

BUG-ID: CLOUDSTACK-1150
Bugfix-for:
Reviewed-by: Wido den Hollander <wido@widodh.nl>
Reported-by: Logan McNaughton <logan@bacoosta.com>
Signed-off-by: Wido den Hollander <wido@widodh.nl> 1360178633 +0100

Conflicts:
	docs/en-US/hypervisor-host-install-libvirt.xml
re-added docs tmp files to .gitignore.
Missing quotes in libvirt configuration instructions. Thanks to  Nux! <nux@li.nux.ro> for finding the issue