Skip installation checks for clangd server if it has already been set up locally.#778

mattn merged 2 commits intomattn:mastermattn/vim-lsp-settings:masterfrom

EugeneSqr:fix_clangd_installation_with_local_clangEugeneSqr/vim-lsp-settings:fix_clangd_installation_with_local_clangCopy head branch name to clipboard