Add an [HGAssetService] section to SQLiteStandalone.ini with the same connection string as [AssetService].

This is necessary because commit 8131a24 (Tue Mar 27 10:08:13 2012) started passing the config section name rather than hardcoding "AssetService"
This meant that the HG external-facing asset service tried to read ConnectionString from [HGAssetService] rather than [AssetService].
On SQLite, not finding this meant that it fell back to [DatabaseService], which is set for OpenSim.db rather than Asset.db.
Therefore, all external asset requests returned null.
Solution taken here is to create an [HGAssetService] section with the same ConnectionString as [AssetService].
This bug does not affect normal MySQL/MSSQL config since they use the [DatabaseService] connection string anyway.
Addresses http://opensimulator.org/mantis/view.php?id=6200, many thanks to DanBanner for identifying the exact problem commit which was very helpful.
This was a regression from OpenSimulator 0.7.3.1 which did not contain this bug.

bin/config-include/storage/SQLiteStandalone.ini

@@ -7,6 +7,16 @@
 [AssetService]
     ConnectionString = "URI=file:Asset.db,version=3"
 
+; The HGAssetService section controls the connection given to the AssetService in a Hypergrid configuration.
+; This has to be separate from [AssetService] because the Hypergrid facing connector uses [HGAssetService] for its config data instead.
+; However, the internal asset service will still use the [AssetService] section.
+; Therefore, you will almost certainly want the ConnectionString in [HGAssetService] to be the same as in [AssetService] 
+; so that they both access the same database.
+; This issue does not apply to normal MySQL/MSSQL configurations, since by default they use the settings in [DatabaseService] and
+; do not have separate connection strings for different services.
+[HGAssetService]
+    ConnectionString = "URI=file:Asset.db,version=3"
+
 [InventoryService]
     ;ConnectionString = "URI=file:inventory.db,version=3"
     ; if you have a legacy inventory store use the connection string below