Correct documentation for the forced-update option

Signed-off-by: Mike Fleetwood <mike.fleetwood@googlemail.com>
Complete removal of MODULE_TAG

Follow on from commit f2e9400

Signed-off-by: Mike Fleetwood <mike.fleetwood@googlemail.com>
Remove old comment in do_update_alias_table()

When commit 216b198 replaced this line:
 -  anychange += update_ok; /* Adjust forced update period on success */
with:
 +  anychange++; /* Adjust forced update period on success */
and removed these lines:
 -  /* Recalculate forced update period */
 -  p_self->forced_update_times = p_self->forced_update_period_sec / p_self->sleep_sec;
the comment became redundant.

Signed-off-by: Mike Fleetwood <mike.fleetwood@googlemail.com>
Write PID file with trailing newline character

The Filesystem Hierarchy Standard, section 5.13 /var/run : Run-time
variable data, says a PID file must contain the PID in ASCII encoded
decimal, followed by a newline character.
    http://www.pathname.com/fhs/2.2/fhs-5.13.html

Signed-off-by: Mike Fleetwood <mike.fleetwood@googlemail.com>