patch 7.4.1646

Problem:    Using Python vim.bindeval() on a partial doesn't work. (Nikolai
            Pavlov)
Solution:   Add VAR_PARTIAL support in Python.

src/version.c

@@ -748,6 +748,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1646,
 /**/
     1645,
 /**/