fixed word typo

Signed-off-by: Sebastien Goasguen <runseb@gmail.com>
Ad ex_security_group_ids argument to the create_node method in the EC driver in
order to be able to launch nodes with security groups on a VPC.

Closes #373

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
improved static address coverage

Closes #390

Signed-off-by: Tomaz Muraus <tomaz@apache.org>