Use msbuild 14 for restoring packages
Use msbuild 14 for restoring packages

msbuild 15 doesn't like the solution file, so we force it to use
version 14 instead.

ermshiperete/LfMerge,sillsdev/LfMerge,sillsdev/LfMerge,sillsdev/LfMerge,ermshiperete/LfMerge,ermshiperete/LfMerge