pixman-renderer: fail to zoom more gracefully
pixman-renderer: fail to zoom more gracefully

When zoom is activated in the pixman rendered the log is filled with warnings
and all rendering stops.  With this patch the warning is generated once and
rendering continues without zooming.

Closes bug 80258

Bug: https://bugs.freedesktop.org/show_bug.cgi?id=80258
Tested-by: Pekka Paalanen <0f6ae7001e34c37b02fb2c1c2573ddf8f442136a@collabora.co.uk>

kwm81/weston,eyolfson/weston,jonnylamb/weston,Gnurou/weston,sir-murray/weston,giucam/weston,Tarnyko/weston-xdg_surface_present,Fantu/compositor-spice,Fantu/compositor-spice,udoprog/weston,krezovic/weston,udoprog/weston,xorgy/weston,Gnurou/weston,mchalupa/weston,Fantu/compositor-spice,kwm81/weston,giucam/weston,Tarnyko/weston-xdg_surface_present,sir-murray/weston,jonnylamb/weston,mchalupa/weston,eyolfson/weston,krezovic/weston,xorgy/weston