Reactivate a group if a contact gets readded

Fixes #723 //FREEBIE

Removes the own number from group on leaving, to receive a proper
re-added message

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -445,6 +445,7 @@ public class ConversationActivity extends PassphraseRequiredSherlockFragmentActi
           OutgoingGroupMediaMessage outgoingMessage = new OutgoingGroupMediaMessage(self, getRecipients(),
                                                                                     context, null);
           MessageSender.send(self, masterSecret, outgoingMessage, threadId);
+          DatabaseFactory.getGroupDatabase(self).remove(groupId, TextSecurePreferences.getLocalNumber(self));
           initializeEnabledCheck();
         } catch (IOException e) {
           Log.w(TAG, e);

src/org/thoughtcrime/securesms/service/GroupReceiver.java

@@ -26,6 +26,7 @@ import static org.whispersystems.textsecure.push.PushMessageProtos.PushMessageCo
 
 public class GroupReceiver {
 
+  private static final String TAG =  GroupReceiver.class.getSimpleName();;
   private final Context context;
 
   public GroupReceiver(Context context) {
@@ -38,12 +39,12 @@ public class GroupReceiver {
                       boolean secure)
   {
     if (!messageContent.getGroup().hasId()) {
-      Log.w("GroupReceiver", "Received group message with no id! Ignoring...");
+      Log.w(TAG, "Received group message with no id! Ignoring...");
       return;
     }
 
     if (!secure) {
-      Log.w("GroupReceiver", "Received insecure group push action! Ignoring...");
+      Log.w(TAG, "Received insecure group push action! Ignoring...");
       return;
     }
 
@@ -60,7 +61,7 @@ public class GroupReceiver {
     } else if (record != null && type == GroupContext.Type.QUIT_VALUE) {
       handleGroupLeave(masterSecret, message, group, record);
     } else if (type == GroupContext.Type.UNKNOWN_VALUE) {
-      Log.w("GroupReceiver", "Received unknown type, ignoring...");
+      Log.w(TAG, "Received unknown type, ignoring...");
     }
   }
 
@@ -117,6 +118,7 @@ public class GroupReceiver {
       group = group.toBuilder().clearName().build();
     }
 
+    if (!groupRecord.isActive()) database.setActive(id, true);
     storeMessage(masterSecret, message, group);
   }