Return instance ips in correct order

The current IP addresses have been returned in random order when
running ruby < 1.9 causing puppet to change the ip addresses on every
puppet run.

Use the method values_in_order to get the attributes in deterministic
order.
Fix spec failures on ruby < 1.9

The spec tests relied on hash.keys returning the hash keys in a specific
order. Since this is not true on all ruby versions and the order in
which the keys appear does actually not matter in any of the affected tests,
make the array comparision order independant.