现象：
The Entity Framework provider type 'System.Data.Entity.SqlServer.SqlProviderServices, EntityFramework.SqlServer' registered in the application config file for the ADO.NET provider with invariant name 'System.Data.SqlClient' could not be loaded. Make sure that the assembly-qualified name is used and that the assembly is available to the running application.
原因：
在测试环境是有EntityFramework.SqlServer.dll 而部署的时候，这个dll没有被放到部署的bin文件夹中。
解决：
从测试环境的obj的文件夹下拷贝到部署所在的bin目录下。