mrt: fix rotation and dump interval handling in table mode
mrt: fix rotation and dump interval handling in table mode

Having two interval options easily confuse users. With this, either
can be specified.

If you specify the rotation interval, gobgpd dumps a table and rotates
a log file every the rotation interval.

Signed-off-by: FUJITA Tomonori <93dac1fe9c4b2a3957982200319981492ad4976e@lab.ntt.co.jp>

Dipsingh/gobgp,osrg/gobgp,tamihiro/gobgp,Dipsingh/gobgp,ishidawataru/gobgp,ishidawataru/gobgp,j-kato/gobgp,fujita/gobgp,fujita/gobgp,tamihiro/gobgp,a16/gobgp,ishidawataru/gobgp,a16/gobgp,tamihiro/gobgp,j-kato/gobgp,osrg/gobgp,j-kato/gobgp,osrg/gobgp,a16/gobgp,a16/gobgp,a16/gobgp,osrg/gobgp,fujita/gobgp,a16/gobgp,tamihiro/gobgp,fujita/gobgp,Dipsingh/gobgp,a16/gobgp