Fix mDNS detection of hosts with the same IP address

This is the case for PCs running GFE and Sunshine side-by-side.

app/src/main/java/com/limelight/computers/ComputerManagerService.java

@@ -431,11 +431,6 @@ public class ComputerManagerService extends Service {
                 }
             }
 
-            @Override
-            public void notifyComputerRemoved(MdnsComputer computer) {
-                // Nothing to do here
-            }
-
             @Override
             public void notifyDiscoveryFailure(Exception e) {
                 LimeLog.severe("mDNS discovery failed");