Avoid warnings from probe

src/Network/Probe.php

@@ -1139,6 +1139,7 @@ class Probe {
 			$data["addr"] = str_replace('acct:', '', $webfinger["subject"]);
 		}
 		$pubkey = "";
+		if (is_array($webfinger["links"])) {
 			foreach ($webfinger["links"] as $link) {
 				if (($link["rel"] == "http://webfinger.net/rel/profile-page")
 					&& ($link["type"] == "text/html")
@@ -1175,6 +1176,7 @@ class Probe {
 					}
 				}
 			}
+		}
 
 		if (isset($data["notify"]) && isset($data["pubkey"])
 			&& isset($data["poll"])