patch 8.0.0340: not checking return valud of dict_add()

Problem:    Not checking return valud of dict_add(). (Coverity)
Solution:   Handle a failure.

Author: brammool

src/buffer.c

@@ -888,8 +888,13 @@ init_changedtick(buf_T *buf)
 	di->di_tv.v_type = VAR_NUMBER;
 	di->di_tv.v_lock = VAR_FIXED;
 	di->di_tv.vval.v_number = 0;
-	dict_add(buf->b_vars, di);
-	buf->b_changedtick = &di->di_tv.vval.v_number;
+	if (dict_add(buf->b_vars, di) == OK)
+	    buf->b_changedtick = &di->di_tv.vval.v_number;
+	else
+	{
+	    vim_free(di);
+	    buf->b_changedtick = &buf->b_ct_val;
+	}
     }
     else
 #endif

src/version.c

@@ -764,6 +764,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    340,
 /**/
     339,
 /**/