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/adbbu/twrpback.cpp b/adbbu/twrpback.cpp
index 2a227ec..c59fd1c 100644
--- a/adbbu/twrpback.cpp
+++ b/adbbu/twrpback.cpp
@@ -514,7 +514,6 @@
 				return -1;
 			}
 		}
-
 		//If we should read from the adb stream, write commands and data to TWRP
 		if (read_from_adb) {
 			std::string cmdstr;
@@ -547,6 +546,7 @@
 							close_restore_fds();
 							return -1;
 						}
+						read_from_adb = false;
 					}
 					else {
 						adblogwrite("ADB TWENDADB crc header doesn't match\n");