Refactor service changed handling

This makes the services changes notification more accurate by waiting until the changes have taken effect and the server re-started before indicating the change.

src/NimBLEServer.cpp

@@ -153,13 +153,12 @@ NimBLEAdvertising* NimBLEServer::getAdvertising() const {
 # endif
 
 /**
- * @brief Sends a service changed notification and resets the GATT server.
+ * @brief Called when the services are added/removed and sets a flag to indicate they should be reloaded.
+ * @details This has no effect if the GATT server was not already started.
  */
 void NimBLEServer::serviceChanged() {
     if (m_gattsStarted) {
         m_svcChanged = true;
-        ble_svc_gatt_changed(0x0001, 0xffff);
-        resetGATT();
     }
 } // serviceChanged
 
@@ -205,6 +204,12 @@ void NimBLEServer::start() {
         }
     }
 
+    // If the services have changed indicate it now
+    if (m_svcChanged) {
+        m_svcChanged = false;
+        ble_svc_gatt_changed(0x0001, 0xffff);
+    }
+
     m_gattsStarted = true;
 } // start
 
@@ -876,7 +881,6 @@ void NimBLEServer::resetGATT() {
         ++it;
     }
 
-    m_svcChanged   = false;
     m_gattsStarted = false;
 } // resetGATT