kernel: allow write access to /data/misc/vold/virtual_disk

The kernel thread which manages this file really needs read/write access
to this file, not read-only. This was suspected in b/36626310 but
apparently something must have changed in the kernel surrounding
permission checking for kernel threads (still unknown)

Bug: 36626310
Bug: 117148019
Bug: 116841589
Test: policy compiles
Change-Id: I9c42541e2567a79b2d741eebf3ddf219f59478a9
1 file changed