fix name of exported files (correct the time)

This reverts part of a75a27ad, where this got changed presumably by mistake.

uhabits-android/src/main/java/org/isoron/uhabits/utils/DatabaseUtils.java

@@ -92,7 +92,7 @@ public abstract class DatabaseUtils
         throws IOException
     {
         SimpleDateFormat dateFormat = DateFormats.getBackupDateFormat();
-        String date = dateFormat.format(DateUtils.getStartOfToday());
+        String date = dateFormat.format(DateUtils.getLocalTime());
         String format = "%s/Loop Habits Backup %s.db";
         String filename = String.format(format, dir.getAbsolutePath(), date);