build_full(): Exit with error for unknown command options

Signed-off-by: Richard T Bonhomme <[email protected]>

easyrsa3/easyrsa

@@ -2887,7 +2887,7 @@ Run easyrsa without commands for usage and commands."
 			nopass)
 				[ "$prohibit_no_pass" ] || EASYRSA_NO_PASS=1
 				;;
-			*) warn "Ignoring unknown command option: '$1'"
+			*) user_error "Unknown command option: '$1'"
 		esac
 		shift
 	done