[NaCl SDK] docs: Remove references to obsolete debugging env vars.

ppapi/native_client/tools/browser_tester/browsertester/browserlauncher.py

 #!/usr/bin/python
 # Copyright (c) 2012 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.
 
 import os.path
 import re
 import shutil
 import sys
 import tempfile
@@ skipping 60 matching lines @@
   if PLATFORM == 'windows' and ' ' in path:
     return '"%s"' % path
   return path
 
 
 def MakeEnv(options):
   env = dict(os.environ)
   # Enable PPAPI Dev interfaces for testing.
   env['NACL_ENABLE_PPAPI_DEV'] = str(options.enable_ppapi_dev)
   if options.debug:
-    env['PPAPI_BROWSER_DEBUG'] = '1'
     env['NACL_PLUGIN_DEBUG'] = '1'
-    env['NACL_PPAPI_PROXY_DEBUG'] = '1'
     # env['NACL_SRPC_DEBUG'] = '1'
   return env
 
 
 class BrowserLauncher(object):
 
   WAIT_TIME = 20
   WAIT_STEPS = 80
   SLEEP_TIME = float(WAIT_TIME) / WAIT_STEPS
 
@@ skipping 247 matching lines @@
              '--ignore=../tools/valgrind/tsan/ignores.txt',
              '--suppressions=../tools/valgrind/tsan/suppressions.txt',
              '--log-file=%s/log.%%p' % (self.tool_log_dir,)] + cmd
     elif self.options.tool != None:
       raise LaunchFailure('Invalid tool name "%s"' % (self.options.tool,))
     if self.options.enable_sockets:
       cmd.append('--allow-nacl-socket-api=%s' % host)
     cmd.extend(self.options.browser_flags)
     cmd.append(url)
     return cmd