Bootstrap os-collect-config during image build

Os-collect-config minimally needs to be told what command to run. The
first time it runs it will detect the Heat and/or ec2 metadata change,
and run os-refresh-config, which will write out its configuration again.
After the command returns os-collect-config is expected to re-execute
itself to grab this configuration.

Change-Id: I3294e251a7a3373adb1e994eef7ada99aab8282a
Merge "Bootstrap os-collect-config during image build"