system mount: unmount system after checking for TWRP app

Change-Id: I9ab74c9839b50e399432d19839191b7de2d1bf60
diff --git a/twrp-functions.cpp b/twrp-functions.cpp
index a3e5a07..8203cfa 100755
--- a/twrp-functions.cpp
+++ b/twrp-functions.cpp
@@ -1313,6 +1313,7 @@
 		}
 	}
 	DataManager::SetValue("tw_app_installed_in_system", 0);
+	PartitionManager.UnMount_By_Path(PartitionManager.Get_Android_Root_Path(), false);
 	return false;
 }
 #endif // ndef BUILD_TWRPTAR_MAIN