fs_config: use libcutils and libselinux shared libraries

- move to libcutils.so and libselinux.so as shared now that
  they are in DISTTOOL.
- liblog dependency is part of libcutils, and need not be
  called out explicitly now. liblog is in DISTTOOL.
- libcutils fs_config has the right to add Android logging

Bug: 19908228
Change-Id: Iaa60ad624b42d83653840ac3c77bfa03ad8674aa