Fix issue of color paints that do not show right color. It is wrong to check if a canvas having valid color paint since it check on a uninitialized variable of paint type. The variable is supposed to be initialized by the paint of the canvas. It is fixed by initialize the variable correctly.

# -*- indent-tabs-mode: t; tab-width: 8; c-basic-offset: 4; -*-
# vim: sw=4:ts=8:sts=4
m4datadir = $(datadir)/mb
dist_m4data_DATA = foreach.m4 mb_c_header.m4 mb_c_source.m4
dist_bin_SCRIPTS = svg2code.py