Remove need to start executor as root

Now that we have a finger gateway, we no longer need to start the
executor as root so that the finger streamer on the executor can
bind to port 79 (default port for the finger streamer is changed
from 79 to 7900). Remove that requirement.

Change-Id: I6df685044c4ce81fd263043adba832609da100af
diff --git a/doc/source/admin/components.rst b/doc/source/admin/components.rst
index 3bec28a..18bbfa3 100644
--- a/doc/source/admin/components.rst
+++ b/doc/source/admin/components.rst
@@ -408,7 +408,7 @@
       Path to command socket file for the executor process.
 
    .. attr:: finger_port
-      :default: 79
+      :default: 7900
 
       Port to use for finger log streamer.
 
@@ -451,13 +451,6 @@
 
       SSH private key file to be used when logging into worker nodes.
 
-   .. attr:: user
-      :default: zuul
-
-      User ID for the zuul-executor process. In normal operation as a
-      daemon, the executor should be started as the ``root`` user, but
-      it will drop privileges to this user during startup.
-
    .. _admin_sitewide_variables:
 
    .. attr:: variables