Use retval, not errno, when stashing master keys

The krb5_db_store_master_key{,_list} functions return a
krb5_error_code, and do not necessarily set errno on failure.
Use the correct variable while reporting errors with com_err().

src/kadmin/dbutil/kdb5_create.c

@@ -341,7 +341,7 @@ void kdb5_create(argc, argv)
                                       &master_keyblock,
                                       mkey_password);
     if (retval) {
-        com_err(progname, errno, _("while storing key"));
+        com_err(progname, retval, _("while storing key"));
         printf(_("Warning: couldn't stash master key.\n"));
     }
     /* clean up */

src/kadmin/dbutil/kdb5_mkey.c

@@ -337,7 +337,7 @@ kdb5_add_mkey(int argc, char *argv[])
                                           &new_mkeyblock,
                                           mkey_password);
         if (retval) {
-            com_err(progname, errno, _("while storing key"));
+            com_err(progname, retval, _("while storing key"));
             printf(_("Warning: couldn't stash master key.\n"));
         }
     }

src/kadmin/dbutil/kdb5_stash.c

@@ -130,7 +130,7 @@ kdb5_stash(argc, argv)
     retval = krb5_db_store_master_key_list(util_context, keyfile, master_princ,
                                            NULL);
     if (retval) {
-        com_err(progname, errno, _("while storing key"));
+        com_err(progname, retval, _("while storing key"));
         exit_status++; return;
     }