Fix authorize security group ingress

[jdrowell]

I was trying to implement "smart" port filtering in EC2 by specifying the security group name in the AWS console by that seems to be broken ("Save" button gets disabled). I then tried amazon-ec2 and got error messages (conflict between parameters). Looking at the most recent API the call seems to have changed. I updated the Authorize and Revoke methods to match the new API and managed to get the calls working. The data shows up correctly in the AWS console (still can't add other thru the console though :(). Modified the tests to match the new API. Use as such in awshell (ids were edited):

ruby-1.9.2-p0 :001 > r = @ec2.revoke_security_group_ingress :group_name => 'MongoDB', :ip_protocol => "tcp", :from_port => "27017", :to_port => "27017", :source_security_group_user_id => '6530123210223', :source_security_group_name => 'MongoDB' => {"xmlns"=>"http://ec2.amazonaws.com/doc/2010-08-31/", "requestId"=>"994023423d-5a49-443e-be5e-01899a806149", "return"=>"true"}