enum: single digit is valid in function enum_query

- is_e164() returns true for a single digit (previously two digits)

modules/enum/enum.c

@@ -254,7 +254,7 @@ static inline int is_e164(str* _user)
 	int i;
 	char c;
 	
-	if ((_user->len > 2) && (_user->len < MAX_NUM_LEN) && ((_user->s)[0] == '+')) {
+	if ((_user->len > 1) && (_user->len < MAX_NUM_LEN) && ((_user->s)[0] == '+')) {
 		for (i = 1; i < _user->len; i++) {
 			c = (_user->s)[i];
 			if ((c < '0') || (c > '9')) return -1;