VS 2017: Upgrade VC++ Compiler and Libraries dialogue in VS when creating a code template project

Pressing "Ok" on the dialogue allows the user to move on and continue working as normal in VS 2017. I was able to work through our hotreload test and a packaging test without issue.

I also noticed this after I opened the UE4.sln file of my GitHub build at CL 3270386 for the first time. Added GitHub as a build type for this bug as a result.

Setup:

1. Have VS 2017 Professional RC installed

Repro:

1. Create a new C++ template project using a binary build from EGL.
2. Observe the dialogue window in Visual Studio 2017

Result:
Visual Studio 2017 prompts a dialogue window warning that projects use an earlier version of the Visual C++ compiler and libraries.

Expected:
Newly created code template project loads into VS without additional dialogue.