monojob_wait() was holding a reference to the completed job, meaning that
various objects would not be freed until the next job was plugged in to
the monojob interface.
Print one dot per second while waiting in monojob.c (e.g. for DHCP,
for file downloads, etc.), to inform user that the system has not
locked up.
Patch contributed by Andrew Schran <aschran@google.com>, minor
modification by me.