Fix chromium committer list specification.

infra/config/cq.cfg

 # See http://luci-config.appspot.com/schemas/projects/refs:cq.cfg for the
 # documentation of this file format.
 
 version: 1
 cq_name: "blink"
 cq_status_url: "https://chromium-cq-status.appspot.com"
 svn_repo_url: "svn://svn.chromium.org/blink/trunk"
 
 rietveld {
   url: "https://codereview.chromium.org"
   project_bases: "^svn\\:\\/\\/svn\\.chromium\\.org\\/blink/trunk(|/.*)$"
   project_bases: "^svn\\:\\/\\/chrome\\-svn\\/blink/trunk(|/.*)$"
   project_bases: "^svn\\:\\/\\/chrome\\-svn\\.corp\\/blink/trunk(|/.*)$"
   project_bases: "^svn\\:\\/\\/chrome\\-svn\\.corp\\.google\\.com\\/blink/trunk(|/.*)$"
   project_bases: "^http\\:\\/\\/src\\.chromium\\.org\\/blink/trunk(|/.*)$"
   project_bases: "^https\\:\\/\\/src\\.chromium\\.org\\/blink/trunk(|/.*)$"
   project_bases: "^https?\\:\\/\\/chromium.googlesource.com\\/chromium\\/blink(?:\\.git)?\\@[a-zA-Z0-9\\-_\\.]+$"
 }
 
 verifiers {
   reviewer_lgtm {
-    committer_list: "project-chromium-committers"
+    committer_list: "external/project-chromium-committers"
   }
 
   tree_status {
     tree_status_url: "https://blink-status.appspot.com"
   }
 
   try_job {
     buckets {
       name: "tryserver.chromium.linux"
       builders { name: "android_arm64_dbg_recipe" }
@@ skipping 30 matching lines @@
     }
 
     buckets {
       name: "tryserver.chromium.win"
       builders { name: "win8_chromium_ng" }
       builders { name: "win_chromium_compile_dbg_ng" }
       builders { name: "win_chromium_rel_ng" }
       builders { name: "win_chromium_x64_rel_ng" }
     }
   }
-  
+
   sign_cla {}
 }