Issue 6108 - No filter list is selected after a migration failure

adblockplus/issue-6108.patch

+Issue 6108 - No filter list is selected after a migration failure
+
+diff --git a/lib/filterStorage.js b/lib/filterStorage.js
+--- a/lib/filterStorage.js
++++ b/lib/filterStorage.js
+@@ -43,16 +43,18 @@ let formatVersion = 5;
+ let FilterStorage = exports.FilterStorage =
+ {
+   /**
+    * Will be set to true after the initial loadFromDisk() call completes.
+    * @type {boolean}
+    */
+   initialized: false,
+ 
++  loadFromDiskFailed: false,
++
+   /**
+    * Version number of the patterns.ini format used.
+    * @type {number}
+    */
+   get formatVersion()
+   {
+     return formatVersion;
+   },
+@@ -398,16 +400,17 @@ let FilterStorage = exports.FilterStorag
+     {
+       return this.restoreBackup(backupIndex, true).then(() =>
+       {
+         if (this.subscriptions.length == 0)
+           return tryBackup(backupIndex + 1);
+       }).catch(error =>
+       {
+         // Give up
++        this.loadFromDiskFailed = true;
+       });
+     };
+ 
+     return IO.statFile(this.sourceFile).then(statData =>
+     {
+       if (!statData.exists)
+       {
+         this.firstRun = true;