tests: update Fedora dockerfile to use Fedora 29

Fedora 29 is the current newest release, so switch to using that
from the current Fedora 28.

Signed-off-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Alex Bennée <alex.bennee@linaro.org>

tests/docker/dockerfiles/fedora.docker

@@ -1,4 +1,4 @@
-FROM fedora:28
+FROM fedora:29
 ENV PACKAGES \
     bc \
     bison \
@@ -82,7 +82,7 @@ ENV PACKAGES \
     tar \
     usbredir-devel \
     virglrenderer-devel \
-    vte3-devel \
+    vte291-devel \
     which \
     xen-devel \
     zlib-devel