Fix crash with font on curve

Was a mistake from recent texspace changes.

Reported by Pablo here in the studio!

source/blender/blenkernel/intern/font.c

@@ -1081,7 +1081,12 @@ makebreak:
 			float minx, maxx, miny, maxy;
 			float timeofs, sizefac;
 
+			if (ob != NULL) {
 				invert_m4_m4(imat, ob->obmat);
+			}
+			else {
+				unit_m4(imat);
+			}
 			copy_m3_m4(imat3, imat);
 
 			copy_m3_m4(cmat, cu->textoncurve->obmat);