[LSP] clangd - Support LspInstall clangd. (#171)

lua/lsp/clangd.lua

@@ -1,3 +1,4 @@
 require'lspconfig'.clangd.setup{
+    cmd = {DATA_PATH .. "/lspinstall/clangd/clangd_11.0.0/bin/clangd"},
     on_attach = require'lsp'.common_on_attach
 }