add "done" after "Updating partition details..."

This addresses a usability problem. Some users are confused when they
switch to the console and see this message, thinking they have to wait.

Examples:
http://forum.xda-developers.com/showthread.php?t=2498492
http://androidforums.com/verizon-galaxy-s3-all-things-root/718376-twrp-recovery-update-question.html

Change-Id: Ib44773998c2ef1b8b821f3b8876218e11a7de357

partitionmanager.cpp

@@ -1281,6 +1281,7 @@ void TWPartitionManager::Update_System_Details(void) {
 #endif
 		}
 	}
+	gui_print("...done\n");
 	DataManager::SetValue(TW_BACKUP_DATA_SIZE, data_size);
 	string current_storage_path = DataManager::GetCurrentStoragePath();
 	TWPartition* FreeStorage = Find_Partition_By_Path(current_storage_path);