Table snapshot: use C*2.1 pattern

[rhardouin]

Not compatible with C*2.0

[rhardouin]

Snapshotting a table doesn't work with C*2.1 because of UUID (it works for whole keyspace).
If we want to handle both 2.0 & 2.1 naming we can drop the -:

table_glob = '%s*' % snapshot_table

But then we can have troubles if a table is a substring of another one e.g.:

users
users_by_email

Let's say we want to backup users only, then we would end up with both tables because of users*.
So we have to make a choice, keep using glob and drop C*2.0 support or scan dirs with a regex.

[tbarbugli]

one option would be to make this configurable (eg. --cassandra-2.0)