remove johannkoenig from libvpx/aom watchlists

Change-Id: I3ffaa32d1c74c325ee2feb9d203f6d4b44f7c326
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2096158
Auto-Submit: Johann Koenig <johannkoenig@google.com>
Reviewed-by: James Zern <jzern@google.com>
Commit-Queue: James Zern <jzern@google.com>
Cr-Commit-Position: refs/heads/master@{#748811}

WATCHLISTS

@@ -2511,12 +2511,10 @@
                           'marcinjb+p4watch@google.com'],
     'language': ['language-reviews@chromium.org'],
     'libaom': ['fgalligan@chromium.org',
-               'johannkoenig@chromium.org',
                'jzern@chromium.org',
                'tomfinegan@chromium.org'],
     'libvpx': ['fgalligan@chromium.org',
                'jianj@chromium.org',
-               'johannkoenig@chromium.org',
                'jzern@chromium.org',
                'marpan@chromium.org',
                'tomfinegan@chromium.org'],