As suggested in https://github.com/docker/docker/pull/14004/files#r34022527
The concern there is we can't differentiate whether user explicitly
asked for an invalid value of -1 or he did not specify anything.
I don't think this would be a problem, because:
- like all other default values like zero, we can't differentiate
user specify it or not, most of which, zeros are also invalid, so
default is default, we show these default values in help info,
so users would know if they set value as default, it'll be like
they set nothing.
- we can't do this kind of string check in REST api request, so
it'll make the behave different from docker command and RESTapi.
Signed-off-by: Qiang Huang <h.huangqiang@huawei.com>
6f8ddec1d0