Add cAdvisor version to VersionInfo.

Sample -
 Version: 
{KernelVersion:3.11.0-17-generic ContainerOsVersion:Ubuntu 14.04 LTS DockerVersion:1.0.0 CadvisorVersion:0.1.0}

Docker-DCO-1.1-Signed-off-by: Rohit Jnagal <jnagal@google.com> (github: rjnagal)