RM: update references after fix in density computation

...ics/RichardsFlow_2d_quasinewton_pcs_0_ts_0_t_0.000000.vtu

...ichardsFlow_2d_quasinewton_pcs_0_ts_104_t_2000.000000.vtu

.../RichardsFlow_2d_quasinewton_pcs_0_ts_19_t_318.000000.vtu

...ics/RichardsFlow_2d_quasinewton_pcs_0_ts_1_t_1.000000.vtu

.../RichardsFlow_2d_quasinewton_pcs_0_ts_29_t_518.000000.vtu

...ics/RichardsFlow_2d_quasinewton_pcs_0_ts_2_t_3.000000.vtu

.../RichardsFlow_2d_quasinewton_pcs_0_ts_39_t_718.000000.vtu

...ics/RichardsFlow_2d_quasinewton_pcs_0_ts_3_t_8.000000.vtu

.../RichardsFlow_2d_quasinewton_pcs_0_ts_49_t_918.000000.vtu

...cs/RichardsFlow_2d_quasinewton_pcs_0_ts_4_t_18.000000.vtu

...RichardsFlow_2d_quasinewton_pcs_0_ts_59_t_1118.000000.vtu

...cs/RichardsFlow_2d_quasinewton_pcs_0_ts_5_t_38.000000.vtu

...RichardsFlow_2d_quasinewton_pcs_0_ts_69_t_1318.000000.vtu

...cs/RichardsFlow_2d_quasinewton_pcs_0_ts_6_t_58.000000.vtu

...RichardsFlow_2d_quasinewton_pcs_0_ts_79_t_1518.000000.vtu

...cs/RichardsFlow_2d_quasinewton_pcs_0_ts_7_t_78.000000.vtu

...RichardsFlow_2d_quasinewton_pcs_0_ts_89_t_1718.000000.vtu

...cs/RichardsFlow_2d_quasinewton_pcs_0_ts_8_t_98.000000.vtu

...RichardsFlow_2d_quasinewton_pcs_0_ts_99_t_1918.000000.vtu

...s/RichardsFlow_2d_quasinewton_pcs_0_ts_9_t_118.000000.vtu