Support activating packages from local paths.

sdk/lib/_internal/pub/test/global/deactivate/path_package_test.dart

+// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
+// for details. All rights reserved. Use of this source code is governed by a
+// BSD-style license that can be found in the LICENSE file.
+
+import 'package:path/path.dart' as p;
+
+import '../../../lib/src/io.dart';
+import '../../descriptor.dart' as d;
+import '../../test_pub.dart';
+
+main() {
+  initConfig();
+  integration('deactivates an active path package', () {
+    d.dir("foo", [
+      d.libPubspec("foo", "1.0.0"),
+      d.dir("bin", [
+        d.file("foo.dart", "main() => print('ok');")
+      ])
+    ]).create();
+
+    schedulePub(args: ["global", "activate", "--source", "path", "../foo"]);
+
+    var path = canonicalize(p.join(sandboxDir, "foo"));
+    schedulePub(args: ["global", "deactivate", "foo"],
+        output: 'Deactivated package foo at path "$path".');
+  });
+}