scd: Make option --homedir work.

* scd/scdaemon.c (opts): Add --homedir.
--
Backport of master commit: def512eb67c8a380f3b873cee0f156deef0b6dda

Without that entry the homedir setting won't work.

GnuPG-bug-id: 2386
Signed-off-by: Werner Koch <wk@gnupg.org>

scd/scdaemon.c

@@ -150,6 +150,7 @@ static ARGPARSE_OPTS opts[] = {
   ARGPARSE_s_s (oDisableApplication, "disable-application", "@"),
   ARGPARSE_s_n (oEnablePinpadVarlen, "enable-pinpad-varlen",
                 N_("use variable length input for pinpad")),
+  ARGPARSE_s_s (oHomedir,    "homedir",      "@"),
 
   ARGPARSE_end ()
 };