let the asset tests run on MySQL. Interesting difference here, the

sqlite driver can handle .Data = Null, the mysql driver can not.  We
should decide which is the right behavior and adjust code for it.

OpenSim/Data/MySQL/Tests/MySQLInventoryTest.cs

@@ -50,6 +50,10 @@ namespace OpenSim.Data.MySQL.Tests
         public void Init()
         {
             SuperInit();
+            // If we manage to connect to the database with the user
+            // and password above it is our test database, and run
+            // these tests.  If anything goes wrong, ignore these
+            // tests.
             try 
             {
                 database = new MySQLManager(connect);
@@ -66,6 +70,10 @@ namespace OpenSim.Data.MySQL.Tests
         [TestFixtureTearDown]
         public void Cleanup()
         {
+            if (db != null)
+            {
+                db.Dispose();
+            }
             if (database != null)
             {
                 database.ExecuteSql("drop table migrations");