correctly cache getSqlDbType map

Author: piaste

src/SqlClient/ISqlCommand.fs

@@ -149,10 +149,10 @@ type ``ISqlCommand Implementation``(cfg: DesignTimeConfig, connection: Connectio
                     sprintf "%s %A" p.ParameterName p.SqlDbType 
 
             // helper map to resolve each parameter's target type
-            let getSqlDbType name = 
+            let getSqlDbType = 
                let lookup = Map.ofSeq <| Seq.zip (parameters     |> Seq.map (fun (name, value) -> name))
                                                  (cmd.Parameters |> Seq.cast<SqlParameter> |> Seq.map (fun p -> p.SqlDbType))
-               Map.find name lookup
+               fun name -> Map.find name lookup
 
             seq {