(bug 55187) archivebot.py: proper handling of command line args

"-family:" is now effective even when "--lang" is not provided.
The first positional arg (script name) is now ignored.

(Follow-up to I97b14b21f3c4c73183f85473926e0b204c4f1abd)

Change-Id: Ia747df50b5736805b0cb1bbfdc2f5d1db180252a
(cherry picked from commit 0da738ee7d39433a79b18dcc6e40af8b07dc7e14)
Merge "(bug 55187) archivebot.py: proper handling of command line args"