selftests: correct define in msg_zerocopy.c

The msg_zerocopy test defines SO_ZEROCOPY if necessary, but its value
is inconsistent with the one in asm-generic.h. Correct that.

Also convert one error to a warning. When the test is complete, report
throughput and close cleanly even if the process did not wait for all
completions.
Reported-by: Dan Melnic <dmm@fb.com>
Signed-off-by: Willem de Bruijn <willemb@google.com>
Acked-by: Alexei Starovoitov <ast@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

tools/testing/selftests/net/msg_zerocopy.c

@@ -59,7 +59,7 @@
 #endif
 
 #ifndef SO_ZEROCOPY
-#define SO_ZEROCOPY	59
+#define SO_ZEROCOPY	60
 #endif
 
 #ifndef SO_EE_CODE_ZEROCOPY_COPIED
@@ -382,7 +382,7 @@ static void do_recv_remaining_completions(int fd)
 	}
 
 	if (completions < expected_completions)
-		error(1, 0, "missing notifications: %lu < %lu\n",
+		fprintf(stderr, "missing notifications: %lu < %lu\n",
 			completions, expected_completions);
 }