Check that hooks directory exists before attempting to call realpath

Closes #2121

lib/tasks/gitlab/check.rake

@@ -485,7 +485,8 @@ namespace :gitlab do
 
         if project.empty_repo?
           puts "repository is empty".magenta
-        elsif File.realpath(project_hook_directory) == File.realpath(gitlab_shell_hooks_path)
+        elsif File.directory?(project_hook_directory) && File.directory?(gitlab_shell_hooks_path) &&
+            (File.realpath(project_hook_directory) == File.realpath(gitlab_shell_hooks_path))
           puts 'ok'.green
         else
           puts "wrong or missing hooks".red
@@ -806,4 +807,3 @@ namespace :gitlab do
     end
   end
 end
-