Removes pushTransaction and copyTransactions request types from HA

there were not used anymore in 2.2 code base. Although tombstones are left
in place to keep the same ordinal as before. The ordinal acts as the
request type ID transfered over the wire.
Merge pull request #2779 from tinwelint/2.2-cleanup-ha-request-types

Removes pushTransaction and copyTransactions request types from HA
Merge branch 'master' into 2.2-merge-2.1

Conflicts:
	community/kernel/src/test/java/org/neo4j/kernel/impl/storemigration/MigrationTestUtils.java
	community/kernel/src/test/java/org/neo4j/kernel/impl/storemigration/UpgradableDatabaseTest.java
	community/neo4j/src/test/java/recovery/TestRecoveryScenarios.java
	community/neo4j/src/test/java/upgrade/StoreMigratorIT.java
	enterprise/ha/src/test/java/org/neo4j/metrics/MetricsLogExtension.java