Set purge delay to 30 seconds

app/src/main/java/eu/faircode/email/ServiceSynchronize.java

@@ -111,7 +111,7 @@ public class ServiceSynchronize extends ServiceBase implements SharedPreferences
     private MutableLiveData<List<TupleAccountState>> liveAccountState = new MutableLiveData<>();
     private MediatorState liveAccountNetworkState = new MediatorState();
 
-    private static final long PURGE_DELAY = 45 * 1000L; // milliseconds
+    private static final long PURGE_DELAY = 30 * 1000L; // milliseconds
     private static final long QUIT_DELAY = 5 * 1000L; // milliseconds
     private static final long STILL_THERE_THRESHOLD = 3 * 60 * 1000L; // milliseconds
     static final int DEFAULT_POLL_INTERVAL = 0; // minutes