fixing multiselect issues for security groups

patched jquery.multi-select so that 'refresh' method would now refresh the select box
fixed multiselect form submission and initial loading issues
moved vpc_id from generic host object to a helper function
vpc_security_group_hash and subnet_vpc_hash added as 'data' attributes on select_f in _ec2.html.erb, they are now accessible without needing to export as JSON in this :onchange attribute
rewrote security_groups method to make it cleaner
cleaned up some test code

FIXED: issue reported by @jmontleon, using an account without a VPC causes an error on _ec2.html.erb
Merge branch 'develop' of github.com:moshea/foreman into develop

Conflicts:
	app/helpers/compute_resources_vms_helper.rb
	app/views/compute_resources_vms/form/_ec2.html.erb

FIXED: issue reported by @jmontleon
error when trying to create an instance without a VPC
- error has being fixed, by checking for mil on compute_resource.security_groups.
However, it turns out, once the default VPC has being removed, instances can no longer be created and
need to contact amazon support to create a default VPC. Also cleaned up the code a little bit, and placed
some logic inside a helper, getting security groups for VPC's