Fixes .net4.6~.net4.71 framework support issue for ssl protocol setting

[ebozduman]

Subnet cusomer hit the error Operation not supported in this platform while creating a certificate identity provider in net462.

That is because System.Net.Http.HttpClientHandler did not support SslProtocols property to set the protocol type for frameworks before net472 release.

So the protocol type is needed to be set using System.Net.ServicePointManager.SecurityProtocol property to support older frameworks like net462.

[martijn00]

@ebozduman can you rebase this one?

[martijn00]

@ebozduman it looks like something went wrong? Did you merge instead of force rebase?

[ebozduman]

I still see the CRLF issue in my branch and I was trying to fix it.

The problem is dotnet regitlint check hits the CRLF => LF issue and not proceeding further during build test.

I think we need to revert the PR #798 to go back to the old .gitattribute setting.
However, text=auto also does not help, so we need to set text=lf first.

I expect this forced commit will be cleaned up when the CRLF => LF replacement PR #802, I've just created at crlf_cleanup branch is merged into this PR.

[martijn00]

@ebozduman maybe its better to just start a new branch from master and copy over these fixes and make a new PR?

[ebozduman]

@martijn00

I agree. I'll create a new PR and close this one.

[ebozduman]

Created a new PR, #836, which supersedes this one.
So, this one is closed.