iotests/162: Fix for newer Linux 5.3+

Linux 5.3 has made 0.0.0.0/8 a working IPv4 subnet.  As such, "42" is
now a valid host, and the connection to it will (hopefully) time out
over a long period rather than quickly return with EINVAL.

So let us use a negative integer for testing that NBD will not crash
when it receives integer hosts.  This way, the connection will again
fail quickly and reliably.

Signed-off-by: Max Reitz <mreitz@redhat.com>
Message-id: 20191002174052.5773-1-mreitz@redhat.com
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Max Reitz <mreitz@redhat.com>

tests/qemu-iotests/162

@@ -46,7 +46,7 @@ echo '=== NBD ==='
 # NBD expects all of its arguments to be strings
 
 # So this should not crash
-$QEMU_IMG info 'json:{"driver": "nbd", "host": 42}'
+$QEMU_IMG info 'json:{"driver": "nbd", "host": -1}'
 
 # And this should not treat @port as if it had not been specified
 # (We need to set up a server here, because the error message for "Connection

tests/qemu-iotests/162.out

 QA output created by 162
 
 === NBD ===
-qemu-img: Could not open 'json:{"driver": "nbd", "host": 42}': Failed to connect socket: Invalid argument
+qemu-img: Could not open 'json:{"driver": "nbd", "host": -1}': address resolution failed for -1:10809: Name or service not known
 image: nbd://localhost:PORT
 image: nbd+unix://?socket=42