Add SSH to configure logging level at runtime

Can configure the logging level of loggers with SSH command. This allows
the admin to change the logging level without restarting the server.

Add additional command to print the logging level of loggers.

Change-Id: I3bd3076bf617607430b86d23ca53d48203afcd76

Documentation/cmd-index.txt

@@ -138,6 +138,12 @@ link:cmd-show-connections.html[gerrit show-connections]::
 link:cmd-show-queue.html[gerrit show-queue]::
 	Display the background work queues, including replication.
 
+link:cmd-logging-ls-level.html[gerrit logging ls-level]::
+    List loggers and their logging level.
+
+link:cmd-logging-set-level.html[gerrit logging set-level]::
+    Set the logging level of loggers.
+
 link:cmd-plugin-install.html[gerrit plugin add]::
     Alias for 'gerrit plugin install'.
 

Documentation/cmd-logging-ls-level.txt

@@ -0,0 +1,43 @@
+= gerrit logging ls-level
+
+== NAME
+gerrit logging ls-level - view the logging level
+
+gerrit logging ls - view the logging level
+
+== SYNOPSIS
+--
+'ssh' -p <port> <host> 'gerrit logging ls-level | ls'
+  <NAME>
+--
+
+== DESCRIPTION
+View the logging level of specified loggers.
+
+== Options
+<NAME>::
+  Display the loggers which contain the input argument in their name. If this
+  argument is not provided, all loggers will be printed.
+
+== ACCESS
+Caller must have the ADMINISTRATE_SERVER capability.
+
+== Examples
+
+View the logging level of the loggers in the package com.google:
+=====
+    $ssh -p 29418 review.example.com gerrit logging ls-level \
+     com.google.
+=====
+
+View the logging level of every logger
+=====
+    $ssh -p 29418 review.example.com gerrit logging ls-level
+=====
+
+GERRIT
+------
+Part of link:index.html[Gerrit Code Review]
+
+SEARCHBOX
+---------

Documentation/cmd-logging-set-level.txt

@@ -0,0 +1,51 @@
+= gerrit logging set-level
+
+== NAME
+gerrit logging set-level - set the logging level
+
+gerrit logging set - set the logging level
+
+== SYNOPSIS
+--
+'ssh' -p <port> <host> 'gerrit logging set-level | set'
+  <LEVEL>
+  <NAME>
+--
+
+== DESCRIPTION
+Set the logging level of specified loggers.
+
+== Options
+<LEVEL>::
+  Required; logging level for which the loggers should be set.
+  'reset' can be used to revert all loggers back to their level
+  at deployment time.
+
+<NAME>::
+  Set the level of the loggers which contain the input argument in their name.
+  If this argument is not provided, all loggers will have their level changed.
+  Note that this argument has no effect if 'reset' is passed in LEVEL.
+
+== ACCESS
+Caller must have the ADMINISTRATE_SERVER capability.
+
+== Examples
+
+Change the logging level of the loggers in the package com.google to DEBUG.
+=====
+    $ssh -p 29418 review.example.com gerrit logging set-level \
+     debug com.google.
+=====
+
+Reset the logging level of every logger to what they were at deployment time.
+=====
+    $ssh -p 29418 review.example.com gerrit logging set-level \
+     reset
+=====
+
+GERRIT
+------
+Part of link:index.html[Gerrit Code Review]
+
+SEARCHBOX
+---------