fixes attributes naming in BCStrategy

...ultiphaseFlow/BoundaryConditions/MultiphaseVelocityBC.cpp

...low/Visitors/MultiphaseBoundaryConditionsBlockVisitor.cpp

...luids/Visitors/RheologyBoundaryConditionsBlockVisitor.cpp

src/cpu/VirtualFluidsCore/BoundaryConditions/BC.h

src/cpu/VirtualFluidsCore/BoundaryConditions/BCStrategy.h

src/cpu/VirtualFluidsCore/BoundaryConditions/DensityBC.cpp

src/cpu/VirtualFluidsCore/BoundaryConditions/NoSlipBC.h

src/cpu/VirtualFluidsCore/BoundaryConditions/SlipBC.cpp

src/cpu/VirtualFluidsCore/BoundaryConditions/VelocityBC.cpp

...ualFluidsCore/Visitors/BoundaryConditionsBlockVisitor.cpp