Revert "Create VertexPlacement on demand in VTableReplicated"

This reverts commit 32f957f3317bd62768b415da0c0cd9114f59782c.

Conflicts:
	graph/src/main/scala/org/apache/spark/graph/impl/GraphImpl.scala
	graph/src/main/scala/org/apache/spark/graph/impl/ReplicatedVertexView.scala