Revert "block: grant IOPRIO_CLASS_RT to CAP_SYS_NICE"

This reverts commit 9d3a39a5 as that
commit causes a bunch of SELinux errors.

Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I73dc15c4ecddcf1950ca7fca2cc107be27da8f3f