lima: can't translate python object to C char* for some camera simulator attributes

This is only for some Lima simulator attributes mode, fill_type, rotation_axis.

This was displayed while scanning stuffs

Error reading lima property mode (TypeError: can't translate python object to C char*)lit_bottom -0.9500
Error reading lima property fill_type (TypeError: can't translate python object to C char*)
Error reading lima property rotation_axis (TypeError: can't translate python object to C char*)

This can be reproduced this way:

DEMO_SESSION [13]: tomocam.camera.fill_type
Error reading lima property fill_type (TypeError: can't translate python object to C char*)
DEMO_SESSION [14]: beamviewer.camera.fill_type
Error reading lima property fill_type (TypeError: can't translate python object to C char*)
DEMO_SESSION [15]: beamviewer.camera.rotation_axis
Error reading lima property rotation_axis (TypeError: can't translate python object to C char*)

What do you think @debionne?