Fix image flashing: attempt 2

We missed a spot!

Change-Id: Ic838f4a23107b4d52d3fb1d7a875e265726c4516
(cherry picked from commit e9a3ee2693df3b9ebe7f501bc93411065559b5f1)
diff --git a/twrpTar.cpp b/twrpTar.cpp
index c18b062..06e3b62 100644
--- a/twrpTar.cpp
+++ b/twrpTar.cpp
@@ -445,7 +445,7 @@
 		part_settings->progress->UpdateDisplayDetails(true);
 
 		if (!part_settings->adbbackup) {
-			InfoManager backup_info(backup_folder + partition_name + ".info");
+			InfoManager backup_info(backup_folder + "/" + partition_name + ".info");
 			backup_info.SetValue("backup_size", size_backup);
 			if (use_compression && use_encryption)
 				backup_info.SetValue("backup_type", COMPRESSED_ENCRYPTED);