Update App.config

Author: perrysk-msft

samples/applications/iot-smart-grid/App.config

@@ -4,7 +4,7 @@
     <supportedRuntime version="v4.0" sku=".NETFramework,Version=v4.5.2" />
   </startup>
   <connectionStrings>
-    <!--<add name="Db" connectionString="Server=tcp:peskount-hktest1.database.windows.net,1433;Database=PowerConsumption;User ID=demovm001@peskount-hktest1;Password=LetAzureIn0_;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;"/>-->
+    <!--<add name="Db" connectionString="Server=tcp:<server>.database.windows.net,1433;Database=PowerConsumption;User ID=<user>;Password=<password>;Encrypt=True;TrustServerCertificate=False;Connection Timeout=30;"/>-->
     <add name="Db" connectionString="Server=.;Database=PowerConsumption;Integrated Security=True"/>
   </connectionStrings>
   <appSettings>