patch 8.1.1551: warning for shadowing popup_dragwin

Problem:    Warning for shadowing popup_dragwin. (Dominique Pelle)
Solution:   Add missing change.

Author: brammool

src/ui.c

@@ -2929,7 +2929,6 @@ jump_to_mouse(
 #endif
 #ifdef FEAT_TEXT_PROP
     static int   in_popup_win = FALSE;
-    static win_T *popup_dragwin = NULL;
 #endif
     static int	prev_row = -1;
     static int	prev_col = -1;

src/version.c

@@ -777,6 +777,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1551,
 /**/
     1550,
 /**/