selftests: fib rule: Drop erroneous TABLE variable

selftests: fib rule: Drop erroneous TABLE variable

The fib_rule6_del_by_pref() and fib_rule4_del_by_pref() functions use
an uninitialised $TABLE variable. They should use $RTABLE instead.
This doesn't alter the result of the test, as it just makes the grep
command less specific (but since the script always uses the same table
number, that doesn't really matter).

Let's fix it anyway and, while there, specify the filtering parameters
directly in 'ip -X rule show' to avoid the extra grep command entirely.

Signed-off-by: Guillaume Nault <gnault@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>