incorrect ccall signature for SQLInstallerError, SQLInstallDriverEx, SQLRemoveDriver

[xitology]

The signature of SQLInstallerError is defined as

(UInt16, Ref{UInt16}, Ptr{UInt8}, UInt16, Ref{UInt16})

while ODBC API Reference specifies it as

RETCODE SQLInstallerError(  
     WORD      iError,  
     DWORD *   pfErrorCode,  
     LPSTR     lpszErrorMsg,  
     WORD      cbErrorMsgMax,  
     WORD *    pcbErrorMsg);  

The second argument has the type DWORD *, which corresponds to Ref{UInt32} rather than Ref{UInt16}.

Similarly, Ref{UInt16} is incorrectly used for a DWORD * argument in SQLInstallDriverEx and SQLRemoveDriver.