DumpLogicalLog: Output format version.

This is crucial for debugging.
Merge pull request #3560 from martinfurmanski/1.9-dump-logical-log-output-format-version

DumpLogicalLog: Output format version.
Merge remote-tracking branch 'upstream/1.9-maint' into 2.0-maint

Conflicts:
	community/kernel/src/main/java/org/neo4j/kernel/impl/util/DumpLogicalLog.java
Merge remote-tracking branch 'upstream/2.0-maint' into 2.1-maint

Conflicts:
	community/kernel/src/main/java/org/neo4j/kernel/impl/transaction/xaframework/LogIoUtils.java
Merge remote-tracking branch 'upstream/2.1-maint'

Conflicts:
	community/kernel/src/main/java/org/neo4j/kernel/impl/transaction/xaframework/VersionAwareLogEntryReader.java
	community/kernel/src/main/java/org/neo4j/kernel/impl/util/DumpLogicalLog.java