Update backuptool for 4.4

Change-Id: I90502938fbca970449e8a853118c13a63e45eaf2
diff --git a/prebuilt/common/bin/backuptool.sh b/prebuilt/common/bin/backuptool.sh
index 9b8bbae..9e67f48 100755
--- a/prebuilt/common/bin/backuptool.sh
+++ b/prebuilt/common/bin/backuptool.sh
@@ -5,7 +5,7 @@
 
 export C=/tmp/backupdir
 export S=/system
-export V=Slim-4.3
+export V=Slim-4.4
 
 # Preserve /system/addon.d in /tmp/addon.d
 preserve_addon_d() {