Fixed #2 - globstars are too permissive

doublestar.go

@@ -203,7 +203,9 @@ func doGlob(basedir string, components, matches []string) (m []string, e error)
     // if the current component is a doublestar, we'll try depth-first
     for _, file := range files {
       if file.IsDir() {
-        m = append(m, filepath.Join(basedir, file.Name()))
+        if lastComponent {
+          m = append(m, filepath.Join(basedir, file.Name()))
+        }
         m, e = doGlob(filepath.Join(basedir, file.Name()), components[patIdx:], m)
       } else if lastComponent {
         // if the pattern's last component is a doublestar, we match filenames, too

doublestar_test.go

@@ -72,6 +72,9 @@ var matchTests = []MatchTest{
   {"**/c", "c", true, nil, true},
   {"**/c", "b/c", true, nil, true},
   {"**/c", "a/b/c", true, nil, true},
+  {"**/c", "a/b", false, nil, true},
+  {"**/c", "abcd", false, nil, true},
+  {"**/c", "a/abc", false, nil, true},
   {"a/**/b", "a/b", true, nil, true},
   {"a/**/c", "a/b/c", true, nil, true},
   {"a/**/d", "a/b/c/d", true, nil, true},