Move BlackOilOnePhaseIndices to Opm namespace

to make it consistent with the rest. #530 development
must have been started before the renaming in #532
and somehow the old namespace survived.

opm/models/blackoil/blackoilonephaseindices.hh

@@ -30,7 +30,7 @@
 
 #include <cassert>
 
-namespace Ewoms {
+namespace Opm {
 
 /*!
  * \ingroup BlackOilModel