daemon: Don't remove the stats timer

daemon: Don't remove the stats timer

We used to free the stats timer whenever the daemon lost the connection
to the build service. Although that should be supported, it could make
the event loop abort because of some unexpected conditions.

This patch simply allocates the timer once and we just arm and disarm it
as needed.

Signed-off-by: Michael Tremer <michael.tremer@ipfire.org>