adding null check for instanceManager
[WFLY-3534] - Updating code to reflect changes from transaction subsystem.
Merge pull request #6678 from The-Alchemist/WFLY-3820

fix for WFLY-3820: adding null check for instanceManager
Merge pull request #6685 from pedroigor/WFLY-3534

[WFLY-3534] - Updating code to reflect changes from transaction subsystem.
WFLY-3443 JCA tracking should default to false for datasources