Fixed off by one error in line drawing code

--HG--
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/trunk%403527

src/video/SDL_draw.h

@@ -325,7 +325,7 @@ do { \
     x = x1; \
     y = y1; \
  \
-    for (i = 1; i < numpixels; ++i) { \
+    for (i = 0; i < numpixels; ++i) { \
         op(x, y); \
         if (d < 0) { \
             d += dinc1; \