Merge pull request #413 from genjosanzo/MULE-7358

Mule 7358: org.mule.config.bootstrap.SimpleRegistryBootstrap.registerTransactionFactories can't handle optional factories
(cherry picked from commit 734e0eb8061611c34d801539be474ef36af5a75d)

Conflicts:
	core/src/test/resources/log4j.properties
Merge pull request #460 from mulesoft/MULE-7358

MULE-7358 - fixing missing license header
(cherry picked from commit f1c27e1eb6a95c1def4193fbdc7bad5563e318f8)