Prevent crash when startService is called but service is already running

AndroidManifest.xml

@@ -200,8 +200,7 @@
 
         <service
             android:name=".LinphoneService"
-            android:label="@string/service_name"
-            android:stopWithTask="false"/>
+            android:label="@string/service_name"/>
         <service
             android:name=".sync.SyncService"
             android:exported="true">

src/android/org/linphone/LinphoneManager.java

@@ -995,9 +995,10 @@ public class LinphoneManager implements CoreListener, SensorEventListener, Accou
 
     public static synchronized void destroy() {
         if (instance == null) return;
-        getInstance().changeStatusToOffline();
+        instance.changeStatusToOffline();
         sExited = true;
         instance.destroyCore();
+        instance = null;
     }
 
     private String getString(int key) {

src/android/org/linphone/LinphoneService.java

@@ -310,6 +310,11 @@ public final class LinphoneService extends Service {
     public int onStartCommand(Intent intent, int flags, int startId) {
         super.onStartCommand(intent, flags, startId);
 
+        if (instance != null) {
+            Log.w("Attempt to start the LinphoneService but it is already running !");
+            return START_REDELIVER_INTENT;
+        }
+
         LinphoneManager.createAndStart(LinphoneService.this);
 
         instance = this; // instance is ready once linphone manager has been created

src/android/org/linphone/receivers/BootReceiver.java

@@ -39,7 +39,7 @@ public class BootReceiver extends BroadcastReceiver {
         } else {
             boolean autostart = LinphonePreferences.instance().isAutoStartEnabled();
             android.util.Log.i("LinphoneBootReceiver", "Device is starting, auto_start is " + autostart);
-            if (autostart) {
+            if (autostart && !LinphoneService.isReady()) {
                 Intent lLinphoneServiceIntent = new Intent(Intent.ACTION_MAIN);
                 lLinphoneServiceIntent.setClass(context, LinphoneService.class);
                 lLinphoneServiceIntent.putExtra("ForceStartForeground", true);