implied pools: cleanup how implied pools are created.
Implied pools help us know where a state comes from. When two branches
are merged we save the pool. sm_states have an ->all_pools which records
every pool that a state is a part of. The first time an sm_state goes
through a pool that is recorded in the ->my_pools. When we merge
sm_states both the ->my_pools and ->all_pools from both sides are copied
to the new state.
This patch cleans up how that is implemented.
Signed-off-by: Dan Carpenter <error27@gmail.com>