Merge pull request #6 from euanh/master

wizard: Make OpenStack's SR the default
wizard: Fix the dom0 memory configuration

The syntax of the kernel parameter was wrong, and it seems best
to make the requested and maximum RAM values equal.

See https://lists.xenserver.org/sympa/arc/xs-devel/2013-08/msg00002.html

Signed-off-by: Euan Harris <euan.harris@citrix.com>