Whoops.  Remove left-over using statements.
Whoops.  Remove left-over using statements.

Change-Id: Ie205192dc27c6e2e4666a00eedb038215286b01f

GoogleCloudPlatform/dotnet-docs-samples,GoogleCloudPlatform/dotnet-docs-samples,GoogleCloudPlatform/dotnet-docs-samples,GoogleCloudPlatform/dotnet-docs-samples