Add integration test over hdfs underfilesystem

In order to avoid some incompatible cases over HDFS UnderFileSystem, here proposes the integration test profile. It can verify the behavior over miniDFSCluster. The simple way to start integration test is 
{
mvn [ -Dhadoop.version=x.x.x] -Dintegration [ -Dufs=tachyon.integration.LocalMiniDFSCluster]
}
Since it is slow to run the integration test, here we disable it by default.