Fixed the test for data/reader/WfsCapabilities.js

Adjustments to the class where needed.
Using the config object know to get Getters and Setters.
This is needed for ExtJS5 and also supported by ExtJS4, so we should use it.
Merge pull request #321 from KaiVolland/data-reader-wfscabapilities-extjs5

Fixed the test for data/reader/WfsCapabilities.js