Don't skip relationships in the cache on rollback.

When loading relationships for a node, and the relationship chain
has been partially loaded, it was possible for another transaction
to make modifications to the next relationship to be loaded for
that node, but without loading it through that node (by loading it
through the other node of that relationship). If that transaction
rolled back it would make the cache skip loading that relationship.
Merge pull request #2769 from thobe/1.9-partial-relchain-load

Don't skip relationships in the cache on rollback.
Merge branch '1.9-maint' into '2.0-maint'.

Conflicts:
	community/kernel/src/main/java/org/neo4j/kernel/impl/nioneo/xa/WriteTransaction.java
	community/kernel/src/test/java/org/neo4j/kernel/impl/core/TestConcurrentModificationOfRelationshipChains.java

Moved changes in WriteTransaction to NeoStoreTransaction.
Updated TestConcurrentModificationOfRelationshipChains to use
transactions for read operations, and to use try-with-resource.
Merge pull request #2773 from thobe/2.0-merge-1.9

Merge 1.9 into 2.0
BACKPORT: Fix inconsistent behavior in diffsets on remove/add combination.

Previously, remove+add would result in an item added, while add+remove
would result in no net changes. This fixes this inconsistency, leading to net
no changes in both cases.

This resolves two bugs in property and label changing, where one would remove
and add the same label or property multiple times in the same transaction.

Conflicts:
	community/kernel/src/main/java/org/neo4j/kernel/impl/api/KernelTransactionImplementation.java
	community/kernel/src/main/java/org/neo4j/kernel/impl/api/StateHandlingStatementOperations.java
	community/kernel/src/test/java/org/neo4j/kernel/impl/api/integrationtest/PropertyIT.java

Conflicts resolved by storing changes in record objects immediately rather
than creating those changes from the TxState upon committing the transaction.
Merge pull request #2776 from thobe/2.0-diffset-semantics

BACKPORT: Fix inconsistent behavior in diffsets on remove/add combination.