[gegl] lens-blur: fix out-of-bounds read

[Ell <ell src gnome org>]

commit 2948033c3a8956fbdc99eeb70131e38d53a026d5
Author: Ell <ell_se yahoo com>
Date:   Sat Jun 6 11:56:14 2020 +0300

    lens-blur: fix out-of-bounds read

 operations/common-cxx/lens-blur.cc | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)
---
diff --git a/operations/common-cxx/lens-blur.cc b/operations/common-cxx/lens-blur.cc
index 71c5ed065..c5624af2f 100644
--- a/operations/common-cxx/lens-blur.cc
+++ b/operations/common-cxx/lens-blur.cc
@@ -364,7 +364,7 @@ process (GeglOperation       *operation,
                   row += 4;
                   row_w++;
 
-                  if (x <= x2)
+                  if (x + 1 <= x2)
                     {
                       for (c = 0; c < 4; c++)
                         accum[c] += row[4 * (+s) + c];