Provide a friendlier error message after Rietveld issue deletion.

git_cl.py

Index: git_cl.py
===================================================================
--- git_cl.py	(revision 116351)
+++ git_cl.py	(working copy)
@@ -446,8 +446,21 @@
   def GetDescription(self, pretty=False):
     if not self.has_description:
       if self.GetIssue():
-        self.description = self.RpcServer().get_description(
-            int(self.GetIssue())).strip()
+        issue = int(self.GetIssue())
+        try:
+          self.description = self.RpcServer().get_description(issue).strip()
+        except urllib2.HTTPError, e:
+          if e.code == 404:
+            DieWithError(
+                ('\nWhile fetching the description for issue %d, received a '
+                 '404 (not found)\nerror. It is likely that you deleted this '

[M-A Ruel, 2012/01/04 19:16:35]

I prefer to have each \n to end the string even if it looks a bit clunky in the
sources. e.g.
('\nWhile fetching the description for issue %d, received a '
 '404 (not found)\n'
 'error. It is likely that you deleted this issue on the '
 'server. If this is the\n'
 'case, please run\n\n'
...

+                 'issue on the server. If this is the\ncase, please run\n\n'
+                 '    git cl issue 0\n\n'
+                 'to clear the association with the deleted issue. Then '
+                 'run this command again.') % issue)
+          else:
+            DieWithError('\nFailed to fetch issue description. HTTP error ' +

[M-A Ruel, 2012/01/04 19:16:35]

I prefer this alignment:

DieWithError(
    '\nFailed to fetch issue description. HTTP error %s' % e.code)

+                         e.code)
       self.has_description = True
     if pretty:
       wrapper = textwrap.TextWrapper()