Refitting fails on manually loaded MHCLO

[joepal1976]

If you load an MHCLO asset via the "load clothes from file" button, mesh refitting will then fail.

04:59.050  bpy.rna          | ERROR Python script error in MPFB_OT_refit_human.execute
04:59.050  operator         | ERROR Python: Traceback (most recent call last):
                            |   File "/home/joepal/source/blender-extensions/repo/mpfb/ui/model/operators/refithuman.py", line 22, in execute
                            |     HumanService.refit(blender_object)
                            |     ~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^
                            |   File "/home/joepal/source/blender-extensions/repo/mpfb/services/humanservice.py", line 1595, in refit
                            |     ClothesService.fit_clothes_to_human(child, basemesh, set_parent=False)
                            |     ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
                            |   File "/home/joepal/source/blender-extensions/repo/mpfb/services/clothesservice.py", line 142, in fit_clothes_to_human
                            |     raise IOError(mhclo_fragment + " does not exist")

This is because there's no MHCLO fragment available, which is obvious since it was not loaded from the library.