busybox currently installs passwd into /usr/bin which prevents its
'full' shadow-utils variant from being installed.
Move the passwd applet to /bin to avoid that collision.
shadow also provides /usr/bin/login which doesn't collide with busybox
as the busybox login applet is installed at /bin/login.
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
