Merge ~cjwatson/launchpad:more-warning-handler-info into launchpad:master

[Colin Watson]

Fix incomplete messages from warning handler

The warning handler sometimes emitted messages like this (with local
paths shortened for brevity):

  The method SimpleViewClass from .../lib/lp/bugs/browser/../templates/buglisting-default.pt._getBatchNavigator
  The doctest <doctest xx-bug-subscriptions.txt[4]>, at the line:
      >>> browser.getControl('Save these changes').click()

This is clearly incomplete. With this change, we instead get:

  The method SimpleViewClass from .../lib/lp/bugs/browser/../templates/buglisting-default.pt._getBatchNavigator
  The doctest <doctest xx-bug-subscriptions.txt[4]>, at the line:
      >>> browser.getControl('Save these changes').click()

  .../env/lib/python2.7/site-packages/lazr/batchnavigator/_batchnavigator.py:82: PendingDeprecationWarning: cgi.parse_qs is deprecated, use urlparse.parse_qs instead
    return cgi.parse_qs(query_string, keep_blank_values=True)

The previous messages were a bit "Shaka, when the walls fell".

[Ioana Lasc (ilasc)]

review: Approve

diff --git a/lib/lp/scripts/utilities/warninghandler.py b/lib/lp/scripts/utilities/warninghandler.py
index 4a489d7..026f69e 100644
--- a/lib/lp/scripts/utilities/warninghandler.py
+++ b/lib/lp/scripts/utilities/warninghandler.py
@@ -22,7 +22,7 @@ class WarningReport:
     def __str__(self):
         info = str(self.info)
         if info:
-            return info
+            return '\n'.join((info, self.message))
         else:
             return self.message