fix for bug in variable size blur compositor node - using incorrect Y blur operations and uninitialized memory was causing random blur results.

source/blender/compositor/operations/COM_BlurBaseOperation.cpp

@@ -121,6 +121,11 @@ float *BlurBaseOperation::make_dist_fac_inverse(int rad, int falloff)
 				val = val * val;
 				break;
 			case PROP_LIN:
+#ifndef NDEBUG
+			/* uninitialized! */
+			case -1:
+				BLI_assert(0);
+#endif
 			default:
 				/* nothing */
 				break;