Fix %fluidsim_load magic
Created originally on Bitbucket by avmo (Ashwin Vishnu)
In [8]: %fluidsim_load -s .
The variables `sim` is defined in your user namespace. Do you really want to overwrite it? [Y/n] y
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Program fluidsim
Load state from file:
[...]ta/SW1Lexlin_test_64x64_S2pix2pi_2019-01-21_16-01-28/state_phys_t000.000.h5
...
In [9]: ls
increments.h5 params_simul.xml spect_energy_budg.h5 spectra2D.h5 state_phys_t001.009.h5 stdout.txt
info_solver.xml pdf.h5 spectra1D.h5 state_phys_t000.000.h5 state_phys_t002.012.h5
Does not load the latest file as expected.