crush: cleanup in crush_do_rule() method

Commit 41ebcc0907c5 ("crush: remove forcefeed functionality") from
May 7, 2012 (linux-next), leads to the following Smatch static
checker warning:

net/ceph/crush/mapper.c:1015 crush_do_rule()
warn: iterator 'j' not incremented

Before commit 41ebcc0907c5 ("crush: remove forcefeed functionality"),
we had this logic:

j = 0;
if (osize == 0 && force_pos >= 0) {
o[osize] = force_context[force_pos];
if (recurse_to_leaf)
c[osize] = force_context[0];
j++; /* <-- this was the only increment, now gone */
force_pos--;
}
/* then crush_choose_*(..., o+osize, j, ...) */

Now, the variable j is dead code — a variable that is set
and never meaningfully varied. This patch simply removes
the dead code.

Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Viacheslav Dubeyko <Slava.Dubeyko@ibm.com>
Reviewed-by: Alex Markuze <amarkuze@redhat.com>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>