Revert "cpuset: Add allow_attach hook for cpusets on android."

This reverts commit da758e20.

Part of Chromium commit series:

CHROMIUM: remove Android's cgroup generic permissions checks

The implementation is utterly broken, resulting in all processes being
allows to move tasks between sets (as long as they have access to the
"tasks" attribute), and upstream is heading towards checking only
capability anyway, so let's get rid of this code.

BUG=b:31790445,chromium:647994
TEST=Boot android container, examine logcat

Signed-off-by: Dmitry Torokhov <dtor@chromium.org>
Reviewed-on: https://chromium-review.googlesource.com/394967


Reviewed-by: Ricky Zhou <rickyz@chromium.org>
Reviewed-by: John Stultz <john.stultz@linaro.org>

Change-Id: I8d8a6ce06d383039615fbd6e1d23f84ce763f31c
Signed-off-by: Amit Pundir <amit.pundir@linaro.org>