Fixes increment bug in mysql's db-assign_sequential_id
Fixes increment bug in mysql's db-assign_sequential_id

sky-xu/deepdive,HazyResearch/deepdive,HazyResearch/deepdive,shahin/deepdive,HazyResearch/deepdive,HazyResearch/deepdive,shahin/deepdive,sky-xu/deepdive