Removes gunsch@ from watchlist / Cast owners.

WATCHLISTS

 # 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.
 
 # Watchlist Rules
 # Refer: http://dev.chromium.org/developers/contributing-code/watchlists
 
 # IMPORTANT: The regular expression filepath is tested against each path using
 # re.search, so it is not usually necessary to add .*.
 
@@ skipping 1278 matching lines @@
     'cast': ['avayvod+watch@chromium.org',
              'imcheng+watch@chromium.org',
              'isheriff+watch@chromium.org',
              'jasonroberts+watch@google.com',
              'miu+watch@chromium.org',
              'xjz+watch@chromium.org'],
     'cc': ['cc-bugs@chromium.org'],
     'certificate_transparency': ['eranm@chromium.org', 'certificate-transparency-chrome@googlegroups.com'],
     'chrome_elf': ['caitkp+watch@chromium.org',],
     'chrome_views': ['tfarina@chromium.org'],
-    'chromecast': ['gunsch+watch@chromium.org',
-                   'halliwell+watch@chromium.org',
+    'chromecast': ['halliwell+watch@chromium.org',
                    'lcwu+watch@chromium.org'],
     'chromecast_public': ['gfhuang+watch@chromium.org'],
     'chromedriver': ['samuong+watch@chromium.org'],
     'chromeos' : ['oshima+watch@chromium.org'],
     'chromeos_attestation' : ['dkrahn+watch@chromium.org'],
     'chromeos_calculator' : ['dharcourt@chromium.org'],
     'chromeos_dbus': ['hashimoto+watch@chromium.org'],
     'chromeos_net' : ['stevenjb+watch@chromium.org'],
     'chromeos_power' : ['derat+watch@chromium.org'],
     'chromeos_login' : ['achuith+watch@chromium.org',
@@ skipping 404 matching lines @@
                        'kinuko+worker@chromium.org',
                        'horo+watch@chromium.org',
                        'falken@chromium.org' ],
     'blink_wtf': [ 'mikhail.pozdnyakov@intel.com',
                    'blink-reviews-wtf@chromium.org' ],
     'blink_xmlhttprequest': [ 'tyoshino+watch@chromium.org' ],
     'test_runner': [ 'jochen+watch@chromium.org',
                      'mlamouri+watch-test-runner@chromium.org' ],
   },
 }