[discretization] fix CMakeLists.txt

dumux/discretization/CMakeLists.txt

 add_subdirectory("box")
 add_subdirectory("cellcentered")
+
+install(FILES
+basefvgridgeometry.hh
+darcyslaw.hh
+evalgradients.hh
+evalsolution.hh
+fickslaw.hh
+fluxstencil.hh
+fluxvariablesbase.hh
+fluxvariablescaching.hh
+fourierslaw.hh
+fvgridvariables.hh
+fvproperties.hh
+methods.hh
+scvandscvfiterators.hh
+scvoperator.hh
+stationaryvelocityfield.hh
+subcontrolvolumebase.hh
+subcontrolvolumefacebase.hh
+upwindscheme.hh
+volumevariables.hh
+DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/dumux/discretization)

dumux/discretization/cellcentered/mpfa/omethod/CMakeLists.txt

@@ -3,4 +3,4 @@ helper.hh
 interactionvolume.hh
 interactionvolumeindexset.hh
 localsubcontrolentities.hh
-DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/dumux/discretization/cellcentered/mpfa)
+DESTINATION ${CMAKE_INSTALL_INCLUDEDIR}/dumux/discretization/cellcentered/mpfa/omethod)