AS7-6500 Add check to make sure method is not overriden on injection
Add remove step handler for the common case of removing a single service
Fix the wording about reporting differences when mgmt versions differ

The messages "reporting/not reporting differences in the model when mgmt
versions are different" were swapped. Fixed that.
[AS7-6551] Add version 2.0 of jboss-as-config schema.  Also update existing configuration based on 1.4 to use 2.0.