stub: allow overriding plugin name with Option

[marquiz]

Use the given name instead of erroring out. The command line flag takes precedence over the NRI_PLUGIN_NAME environment variable.

[marquiz]

@klihub @mikebrow @chrishenzie

[klihub]

@marquiz I had a similar one cooking but we can also take this one in instead.

However, IMO it would be better to not allow/do this for 'pre-launched' plugins (optional configuration picking/relaying uses the name to pick configuration for the plugin). The easiest way to achieve that is to do an os.Getenv(api.PluginSocketEnvVar) == "" check here and otherwise either error out, or give a warning/error but not override the name.

[marquiz]

it would be better to not allow/do this for 'pre-launched' plugins (optional configuration picking/relaying uses the name to pick configuration for the plugin). The easiest way to achieve that is to do an os.Getenv(api.PluginSocketEnvVar) == "" check here and otherwise either error out, or give a warning/error but not override the name.

I see the problem. But can we come up with any less kludge-ish way to solve this? What if we just drop the problematic WithPluginName option from the stub? I still remain my comment in #200 that the naming craziness makes no sense to me.