EventHub: Close opening device before deleting on sysfs change

We must unregister all fds from epoll before closing them to avoid the
fds from remaining open and thus leaking. Prevent fd leaks by
closing any opening device from epoll before closing the Device
via its destructor when the sysfs node changes and triggers a device
reopening.

In this CL, we modify the closeDeviceLocked function to also look at
mOpeningDevices when a device is being closed.

Context: https://idea.popcount.org/2017-03-20-epoll-is-fundamentally-broken-22/

Bug: 397208968
Test: Presubmit
Flag: EXEMPT bug fix
Change-Id: I3de8a9413e68a0b7409e5d0bf56b9d76b7164b49