svn merge -c 1580977 from trunk for HADOOP-10015. UserGroupInformation prints out excessive warnings.

git-svn-id: https://svn.apache.org/repos/asf/hadoop/common/branches/branch-2.4@1580980 13f79535-47bb-0310-9956-ffa450edef68

hadoop-common-project/hadoop-common/CHANGES.txt

@@ -56,6 +56,9 @@ Release 2.4.0 - UNRELEASED
     based on connection properties. (Benoy Antony and Daryn Sharp via
     Arpit Agarwal)
 
+    HADOOP-10015. UserGroupInformation prints out excessive warnings.
+    (Nicolas Liochon via szetszwo)
+
   OPTIMIZATIONS
 
   BUG FIXES

hadoop-common-project/hadoop-common/src/main/java/org/apache/hadoop/security/UserGroupInformation.java

@@ -1548,7 +1548,9 @@ public class UserGroupInformation {
       return Subject.doAs(subject, action);
     } catch (PrivilegedActionException pae) {
       Throwable cause = pae.getCause();
-      LOG.warn("PriviledgedActionException as:"+this+" cause:"+cause);
+      if (LOG.isDebugEnabled()) {
+        LOG.debug("PrivilegedActionException as:" + this + " cause:" + cause);
+      }
       if (cause instanceof IOException) {
         throw (IOException) cause;
       } else if (cause instanceof Error) {