ADB Backup: fix adb restore issues

Set Backup_FileName on adb backup to fix restore.
Set read_from_adb after EOF to return properly
from newer adb client prompt.
Create setter and getter for Backup_FileName
for openrecoveryscript.cpp which is not a
friend class.
Fix condition for twrpTar::Get_Size() and adb backup.
Change-Id: I7eb8168fa3416366b996e220cecbc0e1bcec5e8e
diff --git a/partitions.hpp b/partitions.hpp
index 0f0e6fd..0865c96 100644
--- a/partitions.hpp
+++ b/partitions.hpp
@@ -106,6 +106,8 @@
 	int Decrypt_Adopted();
 	void Revert_Adopted();
 	void Partition_Post_Processing(bool Display_Error);                       // Apply partition specific settings after fstab processed
+	void Set_Backup_FileName(string fname);                                   // Set Backup_FileName for partition
+	string Get_Backup_Name();                                                 // Get Backup_Name for partition
 
 public:
 	string Current_File_System;                                               // Current file system