When disabled, the boto connection will be instantiated without validating
the SSL certificate from the target endpoint. This allows the modules to connect
to Eucalyptus instances running with self-signed certs without errors.
Fixes#3978
Refactor the currently well-factored ec2 modules (i.e. those that already use ec2_connect) to
have a common argument spec. The idea is that new modules can use this spec without duplication
of code, and that new functionality can be added to the ec2 connection code (e.g. security
token argument)
