nilfs_cleanerd: link libraries statically

Make nilfs_cleanerd self-contained in /sbin directory.

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>
install nilfs-* executables to /usr/sbin

 Fixes the following problems (thanks, `adequate`):
  bin-or-sbin-binary-requires-usr-lib-library
    /sbin/nilfs-clean => /usr/lib/x86_64-linux-gnu/libnilfscleaner.so.0
    /sbin/nilfs-clean => /usr/lib/x86_64-linux-gnu/libnilfs.so.0
    /sbin/nilfs-resize => /usr/lib/x86_64-linux-gnu/libnilfs.so.0
    /sbin/nilfs-resize => /usr/lib/x86_64-linux-gnu/libnilfsgc.so.0
    /sbin/nilfs-tune => /usr/lib/x86_64-linux-gnu/libnilfs.so.0
    /sbin/nilfs_cleanerd => /usr/lib/x86_64-linux-gnu/libnilfs.so.0
    /sbin/nilfs_cleanerd => /usr/lib/x86_64-linux-gnu/libnilfsgc.so.0

Signed-off-by: Ryusuke Konishi <konishi.ryusuke@lab.ntt.co.jp>