Revise mining task thread num from 4 to 1.
Revise mining task thread num from 4 to 1.

pombredanne/sf1r-lite,izenecloud/sf1r-ad-delivery,izenecloud/sf1r-lite,izenecloud/sf1r-lite,izenecloud/sf1r-lite,izenecloud/sf1r-ad-delivery,izenecloud/sf1r-lite,pombredanne/sf1r-lite,izenecloud/sf1r-ad-delivery,pombredanne/sf1r-lite,izenecloud/sf1r-ad-delivery,pombredanne/sf1r-lite,izenecloud/sf1r-lite,pombredanne/sf1r-lite,izenecloud/sf1r-ad-delivery