Print snapshot-id when coldsnap is terminated before finishing upload

[arianvp]

When coldsnap is terminated it leaves a pending / error snapshot around. It'd be nice of coldsnap would print out the snapshot-id if it exits uncleanly so it can be removed by the user

[rpkelly]

Hi, could you please clarify the conditions where coldsnap is not returning the snapshot ID? Looking through the errors I'd expect to be thrown on a failed upload return the snapshot-id. Is this in the case of sending a SIGINT while coldsnap is still running?

Would adding a line to the verbose logging that includes the snapshot id as soon as it is created work for what you need? This way that data would always be available, and we wouldn't need to worry about the exit condition for coldsnap.