Only set mdns_registered on success

In setup_mdns_thread mdns_registered should only be set to true
if DNSServiceRegister was successful.

Test: N/A

Change-Id: I8a2798cced91b05b7d8bf5f0df4d16719c581dee
Signed-off-by: Gustav Svensson <gustav.svensson@volvo.corp-partner.google.com>
diff --git a/adb/daemon/mdns.cpp b/adb/daemon/mdns.cpp
index 849378f..3530f48 100644
--- a/adb/daemon/mdns.cpp
+++ b/adb/daemon/mdns.cpp
@@ -74,7 +74,7 @@
 
     if (error != kDNSServiceErr_NoError) {
         LOG(ERROR) << "Could not register mDNS service (" << error << ").";
-        mdns_registered = false;
+        return;
     }
 
     mdns_registered = true;