clean up extension directories without status (#675)
clean up extension directories without status (#675)

* additional logging for extension status

* cleanup extension directories without a valid status

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