Spurious logging if dag is not running when getDAGStatus is invoked.

Remove spurious logging:

2015-03-31 13:50:14,468 INFO [IPC Server handler 0 on 59179] ipc.Server: IPC Server handler 0 on 59179, call org.apache.tez.dag.api.client.rpc.DAGClientAMProtocolBlockingPB.getDAGStatus from 127.0.0.1:59188 Call#123 Retry#0
org.apache.tez.dag.api.TezException: No running dag at present
at org.apache.tez.dag.api.client.DAGClientHandler.getDAG(DAGClientHandler.java:89)
at org.apache.tez.dag.api.client.DAGClientHandler.getACLManager(DAGClientHandler.java:156)
at org.apache.tez.dag.api.client.rpc.DAGClientAMProtocolBlockingPBServerImpl.getDAGStatus(DAGClientAMProtocolBlockingPBServerImpl.java:95)
at org.apache.tez.dag.api.client.rpc.DAGClientAMProtocolRPC$DAGClientAMProtocol$2.callBlockingMethod(DAGClientAMProtocolRPC.java:7465)
at org.apache.hadoop.ipc.ProtobufRpcEngine$Server$ProtoBufRpcInvoker.call(ProtobufRpcEngine.java:619)
at org.apache.hadoop.ipc.RPC$Server.call(RPC.java:962)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2039)
at org.apache.hadoop.ipc.Server$Handler$1.run(Server.java:2035)
at java.security.AccessController.doPrivileged(Native Method)
at javax.security.auth.Subject.doAs(Subject.java:415)
at org.apache.hadoop.security.UserGroupInformation.doAs(UserGroupInformation.java:1628)
at org.apache.hadoop.ipc.Server$Handler.run(Server.java:2033)