Revert "block, cfq: move io_cq exit/release to blk-ioc.c"

This reverts commit f45a5372a368550eff6b57f7287920f27c558bee.
Revert "block, cfq: reorganize cfq_io_context into generic and cfq specific parts"

This reverts commit e22ca9321ef2443dc38f0e8fbd84e619ad167e49.
Revert "block, cfq: kill cic->key"

This reverts commit 74c1299ed035e2179ced3f7f2ef55b832facb2ac.
Revert "block, cfq: unlink cfq_io_context's immediately"

This reverts commit 763d62eafd57ba870ff32ba7b2357d95d7d72210.
Revert "block, cfq: move ioc ioprio/cgroup changed handling to cic"

This reverts commit 42b2e87529aacabdf7b881350270efa83b1598be.
Revert "block, cfq: misc updates to cfq_io_context"

This reverts commit ec3c5ee2cb4a4a28f1d38ea4ef2342de8b88d528.
Revert "block: make ioc get/put interface more conventional and fix race on alloction"

This reverts commit 69a7d184ec2319867427ad6c95e5b42e1b0f3429.
Revert "block: misc ioc cleanups"

This reverts commit 798a164dde1c28fbdd467197d6817f04721bdced.
Revert "CFQ: move think time check variables to a separate struct"

This reverts commit 1eca63c20072f2c0eb756d3e01828a1a59891b14.