apache/spark — pull request #1903 by larryxiao (2014-08-12 08:41:40+00:00)
Title: [SPARK-2062][GraphX] VertexRDD.apply does not use the mergeFunc

create verticesDeduplicate with reduceByKey, using mergeFunc
then proceed with verticesDedup

But this is not tested and I want to add a test on VertexRDD.apply,
because it need Edges, should I place it in VertexRDDSuite or else?