[Libvir] [PATCH] [RUBY-LIBVIRT]: Make the flags parameter optional

All, While using the ruby-libvirt bindings, I usually end up setting the "flags" parameter to various calls to 0. While this is required by the C side of things, for Ruby we have no such constraint; we can have methods with optional arguments. Since most of the time we will be passing "flags" as 0, we will just assume 0 if it isn't specified, and actually use the value in flags if it is. The attached patch does just that. Note that I've only tested about half of the calls in here; further breakage should be easy to find and fix. Also note that this should not impact existing users, since we will honor the flags they are already passing. Signed-off-by: Chris Lalancette <clalance(a)redhat.com&gt;