Add Timeout for donwload of cfgs in dirac-install

[graciani]

The same that is is done for tarballs.

now urlib2 allows to pass a timeout argument.

The optional timeout parameter specifies a timeout in seconds for blocking operations like the connection attempt (if not specified, the global default timeout setting will be used). This actually only works for HTTP, HTTPS and FTP connections.

[atsareg]

Fixed in #691