rebaseline.py: add bug-filing URL to error message

tools/rebaseline.py

Index: tools/rebaseline.py
===================================================================
--- tools/rebaseline.py	(revision 11088)
+++ tools/rebaseline.py	(working copy)
@@ -121,8 +121,11 @@
       self._failures_encountered.append(exc_info)
     else:
       print >> sys.stderr, (
-          'Halting at first exception; to keep going, re-run ' +
-          'with the --keep-going-on-failure option set.')
+          '\nHalting at first exception.\n' +

[epoger, 2013/09/04 20:05:56]

Here's the before-and-after error message.  Any further adjustments to suggest?

BEFORE:

$ tools/rebaseline.py --actuals-base-url BADURL
Halting at first exception; to keep going, re-run with the
--keep-going-on-failure option set.
Traceback (most recent call last):
  File "tools/rebaseline.py", line 418, in <module>
    exception_handler.RaiseExceptionOrContinue()
  File "tools/rebaseline.py", line 416, in <module>
    rebaseliner.RebaselineSubdir(builder=builder)
  File "tools/rebaseline.py", line 264, in RebaselineSubdir
    sections=sections)
  File "tools/rebaseline.py", line 228, in _GetActualResults
    json_contents = self._GetFileContents(json_url)
  File "tools/rebaseline.py", line 204, in _GetFileContents
    return open(filepath, 'r').read()
IOError: [Errno 2] No such file or directory:
'BADURL/Test-Android-GalaxyNexus-SGX540-Arm7-Debug/actual-results.json'


AFTER:

$ tools/rebaseline.py --actuals-base-url BADURL

Halting at first exception.
Please file a bug, containing the following stack trace, at
https://code.google.com/p/skia/issues/entry .

Afterwards, you can re-run with the --keep-going-on-failure option set.

Traceback (most recent call last):
  File "tools/rebaseline.py", line 421, in <module>
    exception_handler.RaiseExceptionOrContinue()
  File "tools/rebaseline.py", line 419, in <module>
    rebaseliner.RebaselineSubdir(builder=builder)
  File "tools/rebaseline.py", line 267, in RebaselineSubdir
    sections=sections)
  File "tools/rebaseline.py", line 231, in _GetActualResults
    json_contents = self._GetFileContents(json_url)
  File "tools/rebaseline.py", line 207, in _GetFileContents
    return open(filepath, 'r').read()
IOError: [Errno 2] No such file or directory:
'BADURL/Test-Android-GalaxyNexus-SGX540-Arm7-Debug/actual-results.json'

[epoger, 2013/09/04 20:08:48]

Updated the message in patchset 2.

+          'Please file a bug, containing the following stack trace, ' +
+          'at https://code.google.com/p/skia/issues/entry .\n\n' +
+          'Afterwards, you can re-run with the --keep-going-on-failure ' +
+          'option set.\n')
       raise exc_info[1], None, exc_info[2]
 
   def ReportAllFailures(self):