Use isql-vt if available (e.g. Ubuntu)
Use isql-vt if available (e.g. Ubuntu)

When installing Virtuoso via APT on Ubuntu, the Virtuoso-specific SQL
interface is called `isql-vt`, in order to avoid clashes with unix-odbc.

See:http://virtuoso.openlinksw.com/dataspace/doc/dav/wiki/Main/VOSMake#The
isql command

To make the install script compatible, it now first checks for the
existence of `isql-vt` before falling back to `isql`.

rawbase/rawbase-server,rawbase/rawbase-server,rawbase/rawbase-server,rawbase/rawbase-server,rawbase/rawbase-server