init trace for work queue before journal init

when journal thread init before the initialization of trace,
it enter into loop (using uninitailized `tid_max`)with
--debug-enable configured. we need to initialize trace before
 journal thread init.
this patch extrace `wq_trace_init` from `init_work_queue` and
call it in the main() function just before the initialization
of journal file.

[Hitoshi: removed inline modifier from declaration of wq_trace_init()
in lib/work.c]

Signed-off-by: Jinzhi Chen <nxtjinzhi@gmail.com>
Signed-off-by: Hitoshi Mitake <mitake.hitoshi@lab.ntt.co.jp>