Log error details when failed to create database

This is to simplify troubleshooting when getting mysterious exceptions
from Azure like "CreateDatabaseAsyncV3 operation failed. Operation
timed out." Having exception type and stacktrace would be helpful.

product/roundhouse/databases/DefaultDatabase.cs

@@ -125,7 +125,7 @@ public virtual bool create_database_if_it_doesnt_exist(string custom_create_data
             {
                 Log.bound_to(this).log_a_warning_event_containing(
                     "{0} with provider {1} does not provide a facility for creating a database at this time.{2}{3}",
-                    GetType(), provider, Environment.NewLine, ex.Message);
+                    GetType(), provider, Environment.NewLine, ex.to_string());
             }
 
             return database_was_created;