Add libvirt_lvm_snapshot_size option

fixes bug 1128581

Prior to Grizzly, snapshots did not work if you were running LVM as
your backing root disk.

It turns out, the documentation never had anything mentioning it
didn't work. So this change is as simple as adding a configuration
variable.

Change-Id: I02de367eff06477727d1fee1a82c34928a76d384
Adding new iptables_regex_{top,bottom} options

fixes bug 1128551

iptables_regex_{top,bottom}, introduced in grizzly, allow operators
to have greater control over what nova does with their iptables.

This patch adds them to the config option list.

Change-Id: I46dbcb331a623f93db828ba5c1d7f38595503d98
Merge "Add libvirt_lvm_snapshot_size option"
Merge "Adding new iptables_regex_{top,bottom} options"