Improvements: * Add "snappy" ssh setup script to run tests in an Ubuntu Snappy (http://www.ubuntu.com/snappy) testbed in QEMU. This uses a given image with -i/--image, or constructs a temporary one using ubuntu-device-flash (which caches its downloads and is fast). * adt-run autopkgtest: Install ubuntu-device-flash and qemu-kvm if available, to run the snappy ssh script tests under autopkgtest in Ubuntu. * ssh setup script "reboot" commands can now simply "exit 10" if they want adt-run to just call "reboot" through ssh, instead of having a custom implementation.
Bug fixes: * tools/adt-setup-vm: Avoid debconf prompts during dist-upgrade. * adt-virt-ssh: Wait for ssh to become available before checking for sudo. Fixes root capability detection for setup scripts which don't already wait for ssh themselves. * VirtSubproc.cmd_reboot: Avoid multi-line shell command so that this also gets along with the ssh runner. * Fix FileNotFoundError if built tree does not have a debian/changelog file. Simply skip detection of source package version in this case.