Remove PYTHONPATH requirement to execute run_slave.py.

slave/run_slave.py

 #!/usr/bin/python
 # Copyright (c) 2010 The Chromium Authors. All rights reserved.
 # Use of this source code is governed by a BSD-style license that can be
 # found in the LICENSE file.
 
 """ Initialize the environment variables and start the buildbot slave.
 """
 
 import os
 import subprocess
@@ skipping 145 matching lines @@
     slave_path = [depot_tools, '/usr/bin', '/bin',
                   '/usr/sbin', '/sbin', '/usr/local/bin']
     os.environ['PATH'] = os.pathsep.join(slave_path)
 
   elif sys.platform == 'cygwin':
     #TODO(maruel): Implement me.
     pass
   else:
     raise NotImplementedError('Unknown platform')
 
+  # Make sure the path is ok before loading buildbot and twisted.
+  sys.path.append(os.path.join('..', 'third_party', 'buildbot_7_12'))

[nsylvain, 2010/11/05 01:24:00]

The reason why it was in makefile is that we could have created a "make
start_bbot8.2" or "run_slave_8_2.bat".

Now you are pretty much forcing us to fork run_slave.py instead, which is going
to be messy once we start having half the masters using one version, and half
the masters using another version.

[M-A Ruel, 2010/11/05 01:51:58]

My plan is to switch all the slaves to 0.8.2 but keep the masters at 0.7.12 and
slowly switch the masters to 0.8.2.

Disagree?

+  sys.path.append(os.path.join('..', 'third_party', 'twisted_8_1'))
+
+  # Reboot the computer when the master tells the slave to terminate.
+  HotPatchSlaveBuilder()
+
   # Run the slave.
-  HotPatchSlaveBuilder()
   import twisted.scripts.twistd as twistd
   twistd.run()
 
 
 if '__main__' == __name__:
   main()