Remove stefan@webrtc.org from libvpx roll notification.

TBR=kjellander@webrtc.org
NOTRY=true

Review-Url: https://codereview.webrtc.org/2159873003
Cr-Commit-Position: refs/heads/master@{#13498}

tools/autoroller/roll_chromium_revision.py

diff --git a/tools/autoroller/roll_chromium_revision.py b/tools/autoroller/roll_chromium_revision.py
index c5f830a..6a7f170 100755
--- a/tools/autoroller/roll_chromium_revision.py
+++ b/tools/autoroller/roll_chromium_revision.py
@@ -274,7 +274,7 @@
                                                   c.current_rev[0:10],
                                                   c.new_rev[0:10]))
       if 'libvpx' in c.path:
-        tbr_authors += 'marpan@webrtc.org, stefan@webrtc.org, '
+        tbr_authors += 'marpan@webrtc.org, '
 
     change_url = CHROMIUM_FILE_TEMPLATE % (rev_interval, 'DEPS')
     commit_msg.append('DEPS diff: %s\n' % change_url)