Summary:
Depends on D19072. Ref T13073. Currently, you can leave leases stranded by using `^C` to interrupt the script. Handle signals and release leases on destruction if they haven't activated yet.
Also, print out more useful information before and after activation.
Test Plan: Mashed ^C while runnning `bin/drydock lease ... --trace`, saw the lease release.
Subscribers: yelirekim, PHID-OPKG-gm6ozazyms6q6i22gyam
Maniphest Tasks: T13073
Differential Revision: https://secure.phabricator.com/D19073
