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

partition.cpp

@@ -2947,3 +2947,11 @@ void TWPartition::Revert_Adopted() {
 	LOGINFO("Revert_Adopted: no crypto support\n");
 #endif
 }
+
+void TWPartition::Set_Backup_FileName(string fname) {
+	Backup_FileName = fname;
+}
+
+string TWPartition::Get_Backup_Name() {
+	return Backup_Name;
+}