move hdinsights package for Go back under preview directory (#5593)

Author: jhendrixMSFT

specification/hdinsight/resource-manager/readme.go.md

@@ -23,7 +23,7 @@ These settings apply only when `--tag=package-2018-06-preview --go` is specified
 Please also specify `--go-sdk-folder=<path to the root directory of your azure-sdk-for-go clone>`.
 
 ``` yaml $(tag) == 'package-2018-06-preview' && $(go)
-output-folder: $(go-sdk-folder)/services/$(namespace)/mgmt/2018-06-01-preview/$(namespace)
+output-folder: $(go-sdk-folder)/services/preview/$(namespace)/mgmt/2018-06-01-preview/$(namespace)
 ```
 
 ### Tag: package-2015-03-preview and go
@@ -33,4 +33,4 @@ Please also specify `--go-sdk-folder=<path to the root directory of your azure-s
 
 ``` yaml $(tag) == 'package-2015-03-preview' && $(go)
 output-folder: $(go-sdk-folder)/services/preview/$(namespace)/mgmt/2015-03-01-preview/$(namespace)
-```
+```