configure: Have git archive generate tar.gz directly
configure: Have git archive generate tar.gz directly

Signed-off-by: Euan Harris <c3b6e83069c8e9e3af49a38fec6026be89559638@citrix.com>

jonludlam/planex,djs55/planex,djs55/planex,euanh/planex-cleanhistory,simonjbeaumont/planex,jonludlam/planex,simonjbeaumont/planex,euanh/planex-cleanhistory,simonjbeaumont/planex,djs55/planex,jonludlam/planex,euanh/planex-cleanhistory