dotnet20: don't delete the v2.0.50727 registry key; deleting it causes dotnet35 to not install
dotnet20: don't delete the v2.0.50727 registry key; deleting it causes dotnet35 to not install

git-svn-id: b92d2e39cfa237656594b3bc53d4cd3ef2bf6eca@674 98bf863f-ac88-fb5c-4855-c94565d26d3c

Winetricks/winetricks,Winetricks/winetricks