tests/qemu-iotests: introduce filter for qemu-nbd export list
Introduce a filter for the output of qemu-nbd export list so it can be
reused in multiple tests.
The filter is a bit more permissive that what test 241 currently uses,
as its allows printing of the export count, along with any possible
error messages that might be emitted.
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Message-Id: <
20220304193610.
3293146-9-berrange@redhat.com>
Tested-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Eric Blake <eblake@redhat.com>