patch 8.0.1398: :packadd does not load packages from the "start" directory

Problem:    :packadd does not load packages from the "start" directory.
            (Alejandro Hernandez)
Solution:   Make :packadd look in the "start" directory if those packages were
            not loaded on startup.

src/version.c

@@ -771,6 +771,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    1398,
 /**/
     1397,
 /**/