Fix log_check_call in docker_daemon.
Merge pull request #164 from dlorenc/pullfix

Fix log_check_call in docker_daemon.
Use DOCKER_LOCKEDMEMORY to set ulimit -l before starting Docker. Very important when applications inside the containers need to lock to large amounts of memory.
Merge pull request #166 from dmerino-va/ulimit-memory-lock

Use DOCKER_LOCKEDMEMORY to set ulimit -l before starting Docker.
Add support for enhanced networking on EC2.

This change adds a provider option, enhanced_networking,
which installs the Intel virtual networking driver for
SR-IOV using DKMS. It also modifies the EC2 AMI registration
to include support for SR-IOV.