include config.h in all unit tests

in some it was already included, so let's fix that inconsistency The
Right Way (TM).

tests/test_SimulationDataContainer.cpp

@@ -17,6 +17,7 @@
   along with OPM.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#include <config.h>
 
 #define BOOST_TEST_MODULE SIMULATION_DATA_CONTAINER_TESTS
 #include <boost/test/unit_test.hpp>