libc-package: fix typo causing annoying diagnostic

libc-package: fix typo causing annoying diagnostic

We don't package /etc/rpc and do_install() makes some effort to remove
that file so as to avoid the "installed but not shipped" diagnostic.  But,
due to a typo in the command line, the file wasn't actually being removed
and the diagnostic continued to be issued.

Signed-off-by: Phil Blundell <philb@gnu.org>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>