Update the R= line with the actual list of reviewers that approved the CL.

gcl.py

Index: gcl.py
diff --git a/gcl.py b/gcl.py
index 6691a601ca03ebb3ee940b3228ec5b27fd3efa66..11d58e07ba5d7d8a3efe05e5ea5b83f3a715f9b4 100755
--- a/gcl.py
+++ b/gcl.py
@@ -299,6 +299,9 @@ class ChangeInfo(object):
   def get_reviewers(self):
     return self._desc.get_reviewers()
 
+  def update_reviewers(self, reviewers):
+    self._desc.update_reviewers(reviewers)
+
   def NeedsUpload(self):
     return self.needs_upload
 
@@ -383,6 +386,11 @@ class ChangeInfo(object):
     self._desc = git_cl.ChangeDescription(
         self.SendToRietveld('/%d/description' % self.issue))
 
+  def GetApprovingReviewers(self):
+    """Returns the issue reviewers list from Rietveld."""
+    return git_cl.get_approving_reviewers(
+        self.rietveld.get_issue_properties(self.issue, False))
+
   def AddComment(self, comment):
     """Adds a comment for an issue on Rietveld.
     As a side effect, this will email everyone associated with the issue."""
@@ -995,6 +1003,8 @@ def CMDcommit(change_info, args):
     # Get the latest description from Rietveld.
     change_info.UpdateDescriptionFromIssue()
 
+  change_info.update_reviewers(change_info.GetApprovingReviewers())
+
   commit_desc = git_cl.ChangeDescription(change_info.description)
   if change_info.issue:
     server = change_info.rietveld