MB-14612 indexer: Primary index should not use prefix compared equality
MB-14612 indexer: Primary index should not use prefix compared equality

For secondary compound keys, we use prefix equality to consider
compound index as another compound or simple index having same
prefix fields. For primary indexes, we should only consider full
index key comparison.

Change-Id: Iafe611d9bbd66cb0422c9a9ce9c41c6613ff3469

jchris/indexing,jchris/indexing,jchris/indexing,jchris/indexing