Remove unnecessary failing test method

Method test006_readCaseInsensitive in TestConfig already does the
same thing, and doesn't require an OS specific test for the value being 
asserted.
This is additionally a fast fix for the failing JUnit test after 
change 3fe5276. 

Change-Id: I96d2794dbc7db55bdd0fbfcf675aabb15cc8419f
Signed-off-by: Stefan Lay <stefan.lay@sap.com>