Adapted tests to changes in PropertiesConfiguration.

PropertiesConfiguration no longer extends AbstractFileConfiguration.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1460442 13f79535-47bb-0310-9956-ffa450edef68
Adapted tests to changes in PropertiesConfiguration.

PropertiesConfiguration no longer extends AbstractFileConfiguration.

git-svn-id: https://svn.apache.org/repos/asf/commons/proper/configuration/trunk@1460443 13f79535-47bb-0310-9956-ffa450edef68