policycoreutils: fixfiles: handle unexpected spaces in command

I accidently ran `fixfiles "a b"` during testing.  Let's fix this too.
Before:

   /sbin/fixfiles: line 394: [: a: binary operator expected

   Usage: ...

After:

    Usage: ...

Signed-off-by: Alan Jenkins <alan.christopher.jenkins@gmail.com>
1 file changed