batman-adv: print client flags in the local/global transtables output

Since clients can have several flags on or off, this patches make them
appear in the local/global transtable output so that they can be checked
for debugging purposes.

Signed-off-by: Antonio Quartulli <ordex@autistici.org>
Signed-off-by: Marek Lindner <lindner_marek@yahoo.de>