The make rules for generating the .stp files forgot to add a dep
on $(tracetool-y) to trigger a rebuild if the trace tool source
changes.

Signed-off-by: Daniel P. Berrange <berrange@redhat.com>
Message-id: 20170728133631.5449-1-berrange@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>