Add supported_dists kwarg to distro detection
Add supported_dists kwarg to distro detection

Signed-off-by: Nathan LeClaire <38947c4d2b13dfd9789405506441b98609e8975e@gmail.com>

rjschwei/WALinuxAgent,rjschwei/WALinuxAgent,hglkrijger/WALinuxAgent,andyliuliming/WALinuxAgent,hglkrijger/WALinuxAgent,Azure/WALinuxAgent,andyliuliming/WALinuxAgent,Azure/WALinuxAgent