backuptool_ab: Pick LineageOS properties from build.prop

* The LineageOS versions properties were removed from the build.prop,
    which is resolved properly in commit:
    "lineage: Keep LineageOS versions properties in build.prop"
    Change-Id: I0060141c097b3d14c3710eee1e0caf7110634967

Change-Id: Ib11670474641d6fd14a00f8421e9fe8d1879bbc2

prebuilt/common/bin/backuptool_ab.sh

@@ -50,7 +50,7 @@ if [ ! -r /system/build.prop ]; then
     return 0
 fi
 
-grep -q "^ro.lineage.version=$V.*" /system/etc/prop.default /system/build.prop && return 1
+grep -q "^ro.lineage.version=$V.*" /system/build.prop && return 1
 
 echo "Not backing up files from incompatible version: $V"
 return 0