Revert "build a correct connection string for mirrored databases, too. In this case "host=ip1:port,ip2:port" servername and dbname are optional but can also be used without host parameter"

This reverts commit 0698cba6.

build a correct connection string for mirrored databases, too. In this case "host=ip1:port,ip2:port"
servername and dbname are optional but can also be used without host parameter

References:
SQLA16 - http://dcx.sybase.com/index.html#sa160/en/dbadmin/serverport-network-conparm.html
SQLA12 - http://infocenter.sybase.com/help/index.jsp?topic=/com.sybase.help.sqlanywhere.11.0.1/dbadmin_en11/serverport-network-conparm.html