busybox

syslogd: avoid spurious ftrunctate() calls for "-b 0"

Forgetting to re-set log_file->size after truncating to zero
discards log-data for the next 1 second following an oversize-induced purge,
when we shouldn't necessarily throw that data away.

Signed-off-by: Joshua Judson Rosen <jrosen@harvestai.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>