test: Make surface demos reproducible by setting colormap to default at start of demo. * bicubic.m, interp2.m, interpn.m, griddata.m, image.m, axis.m, clabel.m, colorbar.m, contour.m, contourf.m, cylinder.m, ezcontour.m, ezcontourf.m, ezmesh.m, ezmeshc.m, ezsurf.m, ezsurfc.m, hold.m, pcolor.m, plotyy.m, quiver3.m, ribbon.m, shading.m, slice.m, sombrero.m, surf.m, surfc.m, surfnorm.m, trisurf.m: Set colormap to default at start of demos to make them reproducible.

--- a/scripts/plot/axis.m	Sun Jan 22 07:43:20 2012 -0800
+++ b/scripts/plot/axis.m	Sun Jan 22 10:02:27 2012 -0800
@@ -489,6 +489,7 @@
 
 %!demo
 %! clf;
+%! colormap ('default');
 %! [x,y,z] = peaks (50);
 %! x1 = max (x(:));
 %! pcolor (x-x1, y-x1/2, z);