The attached patch cleans up the parsing of /proc/xen/balloon that

The attached patch cleans up the parsing of /proc/xen/balloon that
occurs in xend.  Currently, the parsing is hard-coded; it expects that
the desired number is on the first line.  My patch is more robust; it
lets values be retrieved by a label.  It also exposes a few functions to
retrieve the current allocation and the target allocation.

By abstracting this a little better, I'll be able to address a few
other issues in subsequent patches.  Mostly, this allows for better
error checking and guidance for the user.  For example, by exposing
get_dom0_current_alloc(), we can (elsewhere, in a later patch) calculate
how large of a VM could potentially be started.  This is useful, as it
lets simple VM-creation GUIs guide the user towards reasonable memory
values for new VMs.

Signed-off-by:  Charles Coffing <ccoffing@novell.com>