fix: use correct install path for packer (#1540)

lua/bootstrap.lua

@@ -72,6 +72,7 @@ function M:init()
     cache_path = self.cache_path,
     runtime_dir = self.runtime_dir,
     config_dir = self.config_dir,
+    install_path = join_paths(self.runtime_dir, "site", "pack", "packer", "start", "packer.nvim"),
     package_root = join_paths(self.runtime_dir, "site", "pack"),
     compile_path = join_paths(self.config_dir, "plugin", "packer_compiled.lua"),
   }

lua/plugin-loader.lua

@@ -3,11 +3,12 @@ local plugin_loader = {}
 function plugin_loader:init(opts)
   opts = opts or {}
 
+  local install_path = opts.install_path or vim.fn.stdpath "data" .. "/site/pack/packer/start/packer.nvim"
   local package_root = opts.package_root or vim.fn.stdpath "data" .. "/site/pack"
   local compile_path = opts.compile_path or vim.fn.stdpath "config" .. "/plugin/packer_compile.lua"
 
-  if vim.fn.empty(vim.fn.glob(package_root)) > 0 then
-    vim.fn.system { "git", "clone", "--depth", "1", "https://github.com/wbthomason/packer.nvim", package_root }
+  if vim.fn.empty(vim.fn.glob(install_path)) > 0 then
+    vim.fn.system { "git", "clone", "--depth", "1", "https://github.com/wbthomason/packer.nvim", install_path }
     vim.cmd "packadd packer.nvim"
   end