ctdb-scripts: Improve update and listing code

ctdb-scripts: Improve update and listing code

Drop the complexity associated with using awk to escape dots in IPv4
addresses to protect them from sed, and generate a grep -F filter
instead.

For listing, the pipeline is now longer, but the steps are now
clearer:

1. List DB records
2. Extract keys
3. Keep only keys machine hosted public IPs
4. Parse out server IP and client IP
5. Sort

Performance here isn't critical, so having clearer code is preferable.

Use temporary files to avoid command-line length limits.

Also, drop the cd to the queue directory during update.

Signed-off-by: Martin Schwenke <mschwenke@ddn.com>
Reviewed-by: Amitay Isaacs <amitay@gmail.com>