This fix avoids overwritting the previous error messages, ensures the client gets the correct error messages and not just the most recent message during the pull request.
For this `var lastErr` replaced with a slice which acts as a temp place holder for the list of returned error messages for every attempt.
The slice is later joined and returned to the caller function after searching for the image with diffirent versions(v2,v1,v0).
Updated the code with check for no space left on device error occurance and prevent the
daemon on falling back to v1,v0.
Incorporated the comments from @calavera, @RichardScothern, @cpuguy83
Signed-off-by: Anil Belur <askb23@gmail.com>
31cdc63419