Move some utility functions to DiagnosticsHelper, so it can be used by IaaS

Author: yantang-msft

src/ServiceManagement/Common/Commands.ServiceManagement.Common/Commands.ServiceManagement.Common.csproj

@@ -151,7 +151,6 @@
     <Compile Include="CloudBaseCmdlet.cs" />
     <Compile Include="AzureSMCmdlet.cs" />
     <Compile Include="ConfigurationConstants.cs" />
-    <Compile Include="DiagnosticsHelper.cs" />
     <Compile Include="ErrorHelper.cs" />
     <Compile Include="IdnHelper.cs" />
     <Compile Include="ManagementOperationContext.cs" />