selftests: Fix suppress test in fib_tests.sh

selftests: Fix suppress test in fib_tests.sh

[ Upstream commit 6a45d7c64e3ea1cf64d28328c47a67b1ab0f6175 ]

fib_tests is spewing errors:
    ...
    Cannot open network namespace "ns1": No such file or directory
    Cannot open network namespace "ns1": No such file or directory
    Cannot open network namespace "ns1": No such file or directory
    Cannot open network namespace "ns1": No such file or directory
    ping: connect: Network is unreachable
    Cannot open network namespace "ns1": No such file or directory
    Cannot open network namespace "ns1": No such file or directory
    ...

Each test entry in fib_tests is supposed to do its own setup and
cleanup. Right now the $IP commands in fib_suppress_test are
failing because there is no ns1. Add the setup/cleanup and logging
expected for each test.

Fixes: 44308a9c2d23 ("ipv6: do not free rt if FIB_LOOKUP_NOREF is set on suppress rule")
Signed-off-by: David Ahern <dsahern@gmail.com>
Cc: Jason A. Donenfeld <Jason@zx2c4.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>