Don't assume integer revisions on cross builder

tools/bots/cross-vm.py

 #!/usr/bin/python
 # Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 import os
 import re
 import sys
 
 import bot
@@ skipping 15 matching lines @@
 
 def tarball_name(arch, mode, revision):
   return 'cross_build_%s_%s_%s.tar.bz2' % (arch, mode, revision)
 
 def record_names(name, arch, mode):
   return ('record_%s_%s_%s.json' % (name, arch, mode),
           'record_output_%s_%s_%s.json' % (name, arch, mode))
 
 def cross_compiling_builder(arch, mode):
   build_py = os.path.join('tools', 'build.py')
-  revision = int(os.environ['BUILDBOT_GOT_REVISION'])
+  revision = os.environ['BUILDBOT_GOT_REVISION']
   tarball = tarball_name(arch, mode, revision)
   temporary_files = [tarball]
   bot.Clobber()
   try:
     num_run = int(os.environ['BUILDBOT_ANNOTATED_STEPS_RUN'])
     if num_run == 1:
       with bot.BuildStep('Build %s %s' % (arch, mode)):
         run([sys.executable, build_py,
              '-m%s' % mode, '--arch=%s' % arch])
 
@@ skipping 18 matching lines @@
       if os.path.exists(path):
         os.remove(path)
 
 def target_builder(arch, mode):
   test_py = os.path.join('tools', 'test.py')
   test_args = [sys.executable, test_py, '--progress=line', '--report',
                '--time', '--compiler=none', '--runtime=vm', '--write-debug-log',
                '--write-test-outcome-log', '--mode=' + mode, '--arch=' + arch,
                '--exclude-suite=pkg']
 
-  revision = int(os.environ['BUILDBOT_GOT_REVISION'])
+  revision = os.environ['BUILDBOT_GOT_REVISION']
   tarball = tarball_name(arch, mode, revision)
   temporary_files = [tarball]
   bot.Clobber()
   try:
     with bot.BuildStep('Fetch build tarball'):
       run([GSUTIL, 'cp', "%s/%s" % (GCS_BUCKET, tarball), tarball])
 
     with bot.BuildStep('Unpack build tarball'):
       run(['tar', '-xjf', tarball])
 
@@ skipping 23 matching lines @@
     mode = target_vm_pattern_match.group(2)
     target_builder(arch, mode)
   else:
     raise Exception("Unknown builder name %s" % name)
 
 if __name__ == '__main__':
   try:
     sys.exit(main())
   except OSError as e:
     sys.exit(e.errno)