waitForDnsRecord: use subdomain as argument

this allows to hyphenate the subdomain correctly in all places

the original issue was that altDomain in caas was not working
because waitForDnsRecord was not hyphenating.

src/domains.js

@@ -420,18 +420,20 @@ function removeDnsRecords(subdomain, domain, type, values, callback) {
     });
 }
 
-function waitForDnsRecord(fqdn, domain, type, value, options, callback) {
-    assert.strictEqual(typeof fqdn, 'string');
+function waitForDnsRecord(subdomain, domain, type, value, options, callback) {
+    assert.strictEqual(typeof subdomain, 'string');
     assert.strictEqual(typeof domain, 'string');
     assert(type === 'A' || type === 'TXT');
     assert.strictEqual(typeof value, 'string');
     assert(options && typeof options === 'object'); // { interval: 5000, times: 50000 }
     assert.strictEqual(typeof callback, 'function');
 
-    get(domain, function (error, result) {
+    get(domain, function (error, domainObject) {
         if (error) return callback(error);
 
-        api(result.provider).waitForDns(fqdn, result ? result.zoneName : domain, type, value, options, callback);
+        const hostname = fqdn(subdomain, domainObject);
+
+        api(domainObject.provider).waitForDns(hostname, domainObject.zoneName, type, value, options, callback);
     });
 }