12098: Mangle void_p like other swig pointers.

When vtk-python returns a "void *", it passes it as a swig-style
pointer string _0acd876f_void_p which was valid for swig 1.0, but
modern swig requires _0acd876f_p_void instead.

Change-Id: Ic58e66581b7bc56c04e91ec0060b63a8c8e4e445
Merge topic '12098_swig_p_void' into master

e12eb1f4 12098: Mangle void_p like other swig pointers.