WebRTC: Update to new machines after a->b lab move.

masters/master.client.webrtc/slaves.cfg

 # 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.
 
 slaves = [
   # Linux 32-bit.
   {
     'master': 'WebRTC',
     'os': 'linux',
     'version': 'trusty',
@@ skipping 60 matching lines @@
 ] + [
   # Bare-metal Linux 64-bit machines with Android devices connected.
   {
     'master': 'WebRTC',
     'os': 'linux',
     'version': 'trusty',
     'bits': '64',
     'builder': [
       'Android32 Tests (L Nexus5)',
     ],
-    'hostname': 'build1-a3',
+    'hostname': 'build18-b3',
   },
   {
     'master': 'WebRTC',
     'os': 'linux',
     'version': 'trusty',
     'bits': '64',
     'builder': [
       'Android32 Tests (L Nexus5)(dbg)',
     ],
-    'hostname': 'build2-a3',
+    'hostname': 'build19-b3',
   },
 ] + [
   {
     'master': 'WebRTC',
     'os': 'linux',
     'version': 'trusty',
     'bits': '64',
     'builder': [
       'Android32 Tests (L Nexus7.2)',
     ],
-    'hostname': 'build7-a3',
+    'hostname': 'build22-b3',
   },
   {
     'master': 'WebRTC',
     'os': 'linux',
     'version': 'trusty',
     'bits': '64',
     'builder': [
       'Android32 Tests (L Nexus7.2)(dbg)',
     ],
-    'hostname': 'build8-a3',
+    'hostname': 'build21-b3',
   },
   {
     'master': 'WebRTC',
     'os': 'linux',
     'version': 'trusty',
     'bits': '64',
     'builder': [
       'Android64 Tests (L Nexus9)',
     ],
-    'hostname': 'build34-a3',
+    'hostname': 'build17-b3',
   },
 ] + [
   # Mac.
   {
     'master': 'WebRTC',
     'os': 'mac',
     'version': '10.10',
     'bits': '64',
     'builder': [
       'iOS32 Debug',
@@ skipping 71 matching lines @@
 ] + [
   # Windows, bare-metal.
   {
     'master': 'WebRTC',
     'os': 'win',
     'version': 'win7',
     'bits': '64',
     'builder': [
       'Win32 Release [large tests]',
     ],
-    'hostname': 'chromeperf90',
+    'hostname': 'build20-b3',
   }
 ]