Fix variable value assigned twice in succession

Error introduced in rBa7aa0f1a0c24

Mentioned in https://pvs-studio.com/en/blog/posts/cpp/1004/

It could cause the absolute snap to the y direction to fail in
some editor.

source/blender/editors/transform/transform.c

@@ -1725,7 +1725,7 @@ static void initSnapSpatial(TransInfo *t, float r_snap[3], float *r_snap_precisi
 {
   /* Default values. */
   r_snap[0] = r_snap[1] = 1.0f;
-  r_snap[1] = 0.0f;
+  r_snap[2] = 0.0f;
   *r_snap_precision = 0.1f;
 
   if (t->spacetype == SPACE_VIEW3D) {