Setting tag bootmanager-5.3-1

Use TLSv1 to connect to myplc, instead of SSLv3 that is known to be broken
Can implement 'upgrade' in addition to 'reinstall' boot state
upgrade does essentially the same as reinstall except that slices are preserved
upgrade works only on nodes already running containers
because /vservers/ needs to be a btrfs filesystem
pycurl is now a strong requirement (old curl-based code removed)
bugfix for ssh key generation (were all typed rsa1)
a lot of prettification