cap_mkdb: remove igetnext prototype for the function does not exist

[Kevin Lo]

ok?

Index: usr.bin/cap_mkdb/cap_mkdb.c
===================================================================
RCS file: /cvs/src/usr.bin/cap_mkdb/cap_mkdb.c,v
retrieving revision 1.24
diff -u -p -u -p -r1.24 cap_mkdb.c
--- usr.bin/cap_mkdb/cap_mkdb.c 28 Jun 2019 14:20:40 -0000      1.24
+++ usr.bin/cap_mkdb/cap_mkdb.c 15 Sep 2020 03:35:42 -0000
@@ -49,8 +49,6 @@
 void    db_build(char **);
 void    dounlink(void);
 void    usage(void);
-int     igetnext(char **, char **);
-int     main(int, char *[]);
 
 DB *capdbp;
 int verbose;