remove one resize from the online side of the code

src/ZMPRefTrajectoryGeneration/ZMPVelocityReferencedSQP.cpp

src/ZMPRefTrajectoryGeneration/ZMPVelocityReferencedSQP.hh

src/ZMPRefTrajectoryGeneration/nmpc_generator.cpp

src/ZMPRefTrajectoryGeneration/nmpc_generator.hh

tests/TestNaveau2015.cpp