Attempt to fix md5 issue with backups

thanks @bigbiff for the suggestion

Change-Id: Ie9b55537b7fa300461b015d2b9523d4250e755a9
diff --git a/partition.cpp b/partition.cpp
index 00f84a1..31a3f8f 100644
--- a/partition.cpp
+++ b/partition.cpp
@@ -1327,6 +1327,8 @@
 	int index = 0;
 	twrpDigest md5sum;
 
+	sync();
+
 	memset(split_filename, 0, sizeof(split_filename));
 	Full_Filename = restore_folder + "/" + Backup_FileName;
 	if (!TWFunc::Path_Exists(Full_Filename)) {