Fixed segfault on pre-existing subkey update

dist/src/lib/keyring.c

@@ -1374,7 +1374,6 @@ unsigned pgp_add_directsig(
 
     /* Detect duplicate direct sig */
     directsigp = key->directsigs;
-
     for (directsigidx = 0 ; directsigidx < key->directsigc; 
             directsigidx++, directsigp++)
     {
@@ -1477,6 +1476,7 @@ unsigned pgp_update_subkey(
             if(memcmp(subkeyid, subkeyp->id, PGP_KEY_ID_SIZE) == 0 )
             {
                 /* Found same subkey. Detect duplicate sig */
+                subkeysigp = key->subkeysigs;
                 for (subkeysigidx = 0 ; subkeysigidx < key->subkeysigc; 
                         subkeysigidx++, subkeysigp++)
                 {