[CMake] CMake: use new curl

[Bill Hoffman]

Steven Van Ingelgem wrote:
> Hi all,
> 
> 
> How can I (on windows) do the following:
> 
> cmake .. -DCMAKE_USE_NEW_CURL=1
> 
> It always results in an error (upon compilation)?
> Scanning dependencies of target cmcurl

The new curl is currently untested.  So, to avoid the error, don't try 
to use it.

-Bill