Updater: fix wrong preference key in A/B installer

We are referencing the wrong key for deciding whether to delete the
update on reboot.

Change-Id: If83d278259291b61c26302bdd59c2774901b18ca
Signed-off-by: Roman Birg <romanbirg@gmail.com>
diff --git a/src/org/lineageos/updater/controller/ABUpdateInstaller.java b/src/org/lineageos/updater/controller/ABUpdateInstaller.java
index 2524296..866ce16 100644
--- a/src/org/lineageos/updater/controller/ABUpdateInstaller.java
+++ b/src/org/lineageos/updater/controller/ABUpdateInstaller.java
@@ -88,7 +88,7 @@
                     mUpdaterController.notifyUpdateChange(mDownloadId);
                     SharedPreferences pref = PreferenceManager.getDefaultSharedPreferences(
                             mContext);
-                    boolean deleteUpdate = pref.getBoolean(Constants.PREF_AUTO_UPDATES_CHECK,
+                    boolean deleteUpdate = pref.getBoolean(Constants.PREF_AUTO_DELETE_UPDATES,
                             false);
                     if (deleteUpdate) {
                         mUpdaterController.deleteUpdate(mDownloadId);