Handle pruning old format logs, Fixes #2265
Handle backup when no logs are present on target db.
Merge pull request #2331 from jakewins/2.0-backup-with-no-logs

Handle backup when no logs are present on target db.
Merge pull request #2343 from jakewins/1.9-prune-oldlogs

Handle pruning old format logs, Fixes #2265
Merge branch '1.9-maint' into 2.0-merge-1.9

Conflicts:
	community/kernel/src/main/java/org/neo4j/kernel/impl/transaction/xaframework/LogPruneStrategies.java
Merge pull request #2354 from chrisvest/2.0-merge-1.9

2.0 merge 1.9
Include javadocs with the manual.