Infinispan Common Parent POM doesn't follow its schema

The POM of Infinispan Common Parent (parent/pom.xml) is invalid against its schema:

parent/pom.xml:1800: element configuration: Schemas validity error : Element '{http://maven.apache.org/POM/4.0.0}configuration', attribute 'combine.self': The attribute 'combine.self' is not allowed.
parent/pom.xml:1851: element configuration: Schemas validity error : Element '{http://maven.apache.org/POM/4.0.0}configuration', attribute 'combine.self': The attribute 'combine.self' is not allowed.

The commit for JBQA-6819 brings the attribute combine.self for the configuration element. This attribute is not allowed for the configuration element but for its children, see POM Reference:

You can control how child POMs inherit configuration from parent POMs by adding attributes to the children of the configuration element. The attributes are combine.children and combine.self. Use these attributes in a child POM to control how Maven combines plugin configuration from the parent with the explicit configuration in the child.

Checked on 5.2.x branch but the bug is on both branches 5.2.x and master.