Revert "Check block files after removing."

This reverts commit 4f8916f328ef45705a9c72d48c1f68ed34e4670a.
Check block files after succesfully removing a file.
Separate the clearing of block files info to separate functions.
Clear the index info about files when we find they aren't openable.
Simplify CheckBlockFiles routine.

We can do it now that the logic to avoid opening the files several times has been
moved to its own functions.