patch 8.1.0384: sign ordering depends on +netbeans feature

Problem:    Sign ordering depends on +netbeans feature.
Solution:   Also order signs without +netbeans. (Christian Brabandt,
            closes #3224)

src/structs.h

@@ -704,9 +704,7 @@ struct signlist
     linenr_T	lnum;		/* line number which has this sign */
     int		typenr;		/* typenr of sign */
     signlist_T	*next;		/* next signlist entry */
-# ifdef FEAT_NETBEANS_INTG
     signlist_T  *prev;		/* previous entry -- for easy reordering */
-# endif
 };
 
 /* type argument for buf_getsigntype() */