fix: roundup-demo, interactive mode would nuke an existing tracker. Tonu Mikk demonstrated a bug in roundup-demo. When invoked without a tracker home on the command line, it would nuke an existing directory specified interactively. There is still a minor bug. If an invalid home directory is specified, roundup-demo will prompt for the template to use before reporting: Error: Refusing to nuke non-tracker directory: but this doesn't cause data loss so not worth fixing at this time.

# In Python 3 the "anydbm" module was renamed to be "dbm" which is now a
# package containing the various implementations. The "wichdb" module's
# whichdb() function was moved to the new "dbm" module.

try:
    # old school first because <3 had a "dbm" module too...
    import anydbm
    from whichdb import whichdb
except ImportError:
    # python 3+
    import dbm as anydbm
    whichdb = anydbm.whichdb