Allow three IOCTLs to be used on suspended pool, restoring state that
existed before IOCTL code refactoring merged change 4445fffb from illumos
at r248571.

This change allows `zpool clear` to be used again to recover suspended pool.
It seems the only was supposed by the code to restore pool operation after
reconnecting lost disks that were required for data completeness.  There
are still cases where `zpool clear` command can just safely stuck due to
deadlocks inside ZFS kernel part, but probably that is better then having
no chances to recover at all.

(cherry picked from commit c034c95e67abdb7eef95a34c9dc188f227a085cf)