gclient flatten: preserve vars in pinned deps

Bug: 570091
Change-Id: I8c450da68fd36d166f8f838c645672fce7c03891
Reviewed-on: https://chromium-review.googlesource.com/610004
Reviewed-by: Michael Moss <mmoss@chromium.org>
Reviewed-by: Dirk Pranke <dpranke@chromium.org>
Commit-Queue: Paweł Hajdan Jr. <phajdan.jr@chromium.org>
diff --git a/gclient.py b/gclient.py
index 9e3ed81..e46556e 100755
--- a/gclient.py
+++ b/gclient.py
@@ -1739,8 +1739,9 @@
           continue
         scm = gclient_scm.CreateSCM(
             dep.parsed_url, self._client.root_dir, dep.name, dep.outbuf)
-        dep._parsed_url = dep._raw_url = dep._url = '%s@%s' % (
-            url, scm.revinfo(self._client._options, [], None))
+        revinfo = scm.revinfo(self._client._options, [], None)
+        dep._parsed_url = dep._url = '%s@%s' % (url, revinfo)
+        dep._raw_url = '%s@%s' % (dep._raw_url, revinfo)
 
     self._deps_string = '\n'.join(
         _GNSettingsToLines(