CLOUDSTACK-1120 [EC2 Query API] Parameter 'keynames' is not honoured by DescribeKeyPairs

When EC2DesribeKeyPairs is called with filter 'keynames' it ignored the key-name provided and lists all the key-pairs
CLOUDSTACK-1121: [EC2 Query API] RunInstances, instance is always deployed in the default security group

During EC2RunInstances, even if the security group the instance is to be deployed in specified the instance gets deployed in the default security group
CLOUDSTACK-1112 [EC2 Query API] DescribeSnapshots fails, when an invalid 'snapshotId' parameter is provided
CLOUDSTACK-1124 [EC2 Query API] Improve the logging. Having empty response objects is harmless to functionality

This is observed in the awsapi.log for all Describe* EC2 commands when the response object returned by CS has no elements. But with EC2DescribeImages command it is always observed. This is because every time DescribeImage is fired, we call CS listTemplates command multiple times, each time setting a different value for the templateFilter parameter (e.g. featured, executable, community etc.). And for some of these CS calls made we obtain am empty response and hence the message in the logs.
CLOUDSTACK-1136: [EC2 Query API] AssociateAdress, DisassociateAddress and ReleaseAddress fail with NPE

When invalid parameter is provided as input for any of these API's we get an NPE