AMBARI-6475. Set loglevel to WARN for releases, and fix warnings/deprecations.(vbrodetskyi)

ambari-server/src/main/resources/stacks/HDP/2.0.6/hooks/before-START/files/task-log4j.properties

@@ -129,4 +129,6 @@ log4j.appender.NullAppender=org.apache.log4j.varia.NullAppender
 # Sends counts of logging messages at different severity levels to Hadoop Metrics.
 #
 log4j.appender.EventCounter=org.apache.hadoop.log.metrics.EventCounter
-
+ 
+# Removes "deprecated" messages
+log4j.logger.org.apache.hadoop.conf.Configuration.deprecation=WARN

ambari-server/src/main/resources/stacks/HDP/2.0.6/services/HDFS/configuration/hdfs-log4j.xml

@@ -190,6 +190,9 @@ log4j.appender.NullAppender=org.apache.log4j.varia.NullAppender
 # Sends counts of logging messages at different severity levels to Hadoop Metrics.
 #
 log4j.appender.EventCounter=org.apache.hadoop.log.metrics.EventCounter
+
+# Removes "deprecated" messages
+log4j.logger.org.apache.hadoop.conf.Configuration.deprecation=WARN
     </value>
   </property>