Check for metafiles only in the root directory

Library/Homebrew/keg.rb

@@ -207,9 +207,8 @@ class Keg
   alias eql? ==
 
   def empty_installation?
-    Pathname.glob("#{path}/**/*") do |file|
-      return false if file.executable?
-      next if file.directory?
+    Pathname.glob("#{path}/*") do |file|
+      return false if file.directory? && !file.children.reject(&:ds_store?).empty?
       basename = file.basename.to_s
       next if Metafiles.copy?(basename)
       next if %w[.DS_Store INSTALL_RECEIPT.json].include?(basename)

Library/Homebrew/test/keg_test.rb

@@ -59,6 +59,10 @@ class LinkTests < LinkTestCase
 
     (@keg/"bin").rmtree
     assert_predicate @keg, :empty_installation?
+
+    (@keg/"bin").mkpath
+    touch @keg.join("bin", "todo")
+    refute_predicate @keg, :empty_installation?
   end
 
   def test_linking_keg