[R10] fix issues #770 and #778

[feich-ms]

fix issue #770 and issue #778.

[vishwacsena]

@feich-ms can we add tests?

[feich-ms]

@vishwacsena, unit tests for locale issue are added but the endpoint feature cannot be tested by unit tests as it needs to be with config:set:luis command. I did manual tests in package/cli/bin folder with below cmd

1. run config:set:luis --endpoint https://chinaeast2.api.cognitive.azure.cn
2. run luis:build --in a.zh-cn.lu --authoringKey xxx --out . --suffix feich --botName test --region chinaeast2 --fallbackLocale zh-cn

And it works well when I'm using the authoringKey from https://luis.azure.cn/