Change ninja rpath generation to be more like make.

test/linux/implicit-rpath/test.gyp

+# Copyright (c) 2013 Google Inc. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+{
+  'targets': [
+    {
+      'target_name': 'shared',
+      'type': 'shared_library',
+      'sources': [ 'file.c' ],
+    },
+    {
+      'target_name': 'static',
+      'type': 'static_library',
+      'sources': [ 'file.c' ],
+    },
+    {
+      'target_name': 'shared_executable',
+      'type': 'executable',
+      'sources': [ 'main.c' ],
+      'dependencies': [
+        'shared',
+      ]
+    },
+    {
+      'target_name': 'static_executable',
+      'type': 'executable',
+      'sources': [ 'main.c' ],
+      'dependencies': [
+        'static',
+      ]
+    },
+  ],
+}