CLI command to log something for ease of debugging.

onos> mark --impersonate org.onosproject.stc Starting step FOO
onos> display | tail -n 2
2017-05-06 01:34:57,275 | INFO  | r user y-higuchi | stc                              | 137 - org.onosproject.onos-cli - 1.10.0.SNAPSHOT | Starting step FOO

Change-Id: I548ae2470b333a2ac047d8c7782b4a1b79535dbb
diff --git a/cli/src/main/resources/OSGI-INF/blueprint/shell-config.xml b/cli/src/main/resources/OSGI-INF/blueprint/shell-config.xml
index 85dde80..1f0a70d 100644
--- a/cli/src/main/resources/OSGI-INF/blueprint/shell-config.xml
+++ b/cli/src/main/resources/OSGI-INF/blueprint/shell-config.xml
@@ -18,6 +18,10 @@
     <command-bundle xmlns="http://karaf.apache.org/xmlns/shell/v1.1.0">
 
         <command>
+            <action class="org.onosproject.cli.MarkCommand"/>
+        </command>
+
+        <command>
             <action class="org.onosproject.cli.PrettyJson"/>
         </command>