Android 5.1系统默认必须在蓝牙开关设置界面才能被手机等外部设备搜索的到，因需求改为默认打开被发现模式以便手机等外部设备搜索的到蓝牙

diff --git a/packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterProperties.java b/packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterProperties.java
index f89404e4d7..c06b167084 100644
--- a/packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterProperties.java
+++ b/packages/apps/Bluetooth/src/com/android/bluetooth/btservice/AdapterProperties.java
@@ -591,6 +591,9 @@ class AdapterProperties {
                     /* though not always required, this keeps NV up-to date on first-boot after flash */
                     setDiscoverableTimeout(mDiscoverableTimeout);
             }
+                    setScanMode(AbstractionLayer.BT_SCAN_MODE_CONNECTABLE_DISCOVERABLE);
+                    setDiscoverableTimeout(mDiscoverableTimeout);
         }
     }