Add VERBOSE_NO_TIMESTAMP flag

As described in the documentation, this flag is intended for the case
where the console output is being captured by a tool that appends its
own timestamps.

In the gate this is the job-output.txt.  We want the console output as
people like to watch that scrolling by as part of the live console
log.  Although this gets saved to job-output.txt, we still want to
keep logging to the individual log files even though it's technically
a duplicate -- in the multinode case the job-output.txt gets
interleaved by all the running nodes; it's much easier to just look at
the individual log files.  Also, people are used to it where it is :)

Change-Id: I3486636f1c76139581f6cd9668426f507b7c621d
diff --git a/doc/source/configuration.rst b/doc/source/configuration.rst
index 49cad05..1d02395 100644
--- a/doc/source/configuration.rst
+++ b/doc/source/configuration.rst
@@ -286,6 +286,18 @@
 
         LOG_COLOR=False
 
+When using the logfile, by default logs are sent to the console and
+the file.  You can set ``VERBOSE`` to ``false`` if you only wish the
+logs to be sent to the file (this may avoid having double-logging in
+some cases where you are capturing the script output and the log
+files).  If ``VERBOSE`` is ``true`` you can additionally set
+``VERBOSE_NO_TIMESTAMP`` to avoid timestamps being added to each
+output line sent to the console.  This can be useful in some
+situations where the console output is being captured by a runner or
+framework (e.g. Ansible) that adds its own timestamps.  Note that the
+log lines sent to the ``LOGFILE`` will still be prefixed with a
+timestamp.
+
 Logging the Service Output
 ~~~~~~~~~~~~~~~~~~~~~~~~~~