Update create_schema_mssql.cmd

Support for installing geoportal when SQL Server named instance is configured to use a fixed port:
http://msdn.microsoft.com/en-us/library/ms177440(v=sql.105).aspx

Wrap the first parameter in quotes and provide the custom port number with a comma.  
Sample Input: create_schema_mssql "mymachine,myport" geoportal geoportal geoportalpwd