Bug 744644 - Mark migration as finished if there is no database. r=lucasr

mobile/android/base/ProfileMigrator.java

@@ -801,6 +801,9 @@ public class ProfileMigrator {
             File dbFile = new File(dbPath);
             if (!dbFile.exists()) {
                 Log.i(LOGTAG, "No database");
+                // Nothing to do, so mark as done.
+                setMigratedBookmarks();
+                setMigratedHistory();
                 return;
             }
             File dbFileWal = new File(dbPathWal);