AOSP: e2fsdroid: read and enforce android's permissions

AOSP: e2fsdroid: read and enforce android's permissions

Set the permissions and the extended attributes as defined by fs_config
and selinux.

Test: create an image with make_ext4 and with mke2fs + e2fsdroid
      Compare the output of:
      for f in `find . | sort`; do
          xattr -l "$f"; md5sum "$f" ls -lah "$f"
      done

Change-Id: I64c97f81c7f5e2bcf3cee3431e410d064cf0735a
From AOSP commit: 4c1e1f46301b3ff7f60be1d8e943ecc23b917ca7

Signed-off-by: Theodore Ts'o <tytso@mit.edu>