Move function to concrete class instead of abstract...

...so this probably should have been moved when I moved the rest.
It worked as is but did make things domain specific in the 'abstract'.

src/WhoisServerList/AbstractLocator.php

@@ -1,8 +1,6 @@
 <?php
 namespace MallardDuck\Whois\WhoisServerList;
 
-use MallardDuck\Whois\Exceptions\UnknownWhoisException;
-
 /**
  * Whois Server List Locator Class
  *
@@ -94,16 +92,5 @@ abstract public function findWhoisServer($domain);
      *
      * @return string         Returns the domain name of the whois server.
      */
-    public function getWhoisServer($domain = '')
-    {
-        if (!empty($domain) || empty($this->lastMatch)) {
-            $this->findWhoisServer($domain);
-        }
-        $server = current($this->lastMatch);
-        if ('UNKNOWN' === strtoupper($server)) {
-            throw new UnknownWhoisException("This domain doesn't have a valid whois server.");
-        }
-
-        return $server;
-    }
+    abstract public function getWhoisServer($domain = '');
 }

src/WhoisServerList/DomainLocator.php

@@ -48,4 +48,24 @@ public function findWhoisServer($domain)
 
         return $this;
     }
+
+    /**
+     * Get the Whois server of the domain provided, or previously found domain.
+     *
+     * @param  string $domain The domain being looked up via whois.
+     *
+     * @return string         Returns the domain name of the whois server.
+     */
+    public function getWhoisServer($domain = '')
+    {
+        if (!empty($domain) || empty($this->lastMatch)) {
+            $this->findWhoisServer($domain);
+        }
+        $server = current($this->lastMatch);
+        if ('UNKNOWN' === strtoupper($server)) {
+            throw new UnknownWhoisException("This domain doesn't have a valid whois server.");
+        }
+
+        return $server;
+    }
 }