dockerfiles: add diffutils to Fedora

For some reason diffutils is not included in the Fedora containers anymore,
causing the build to fail.

Signed-off-by: Paolo Bonzini <[email protected]>
Reviewed-by: Neal Gompa <[email protected]>
Reviewed-by: Philippe Mathieu-Daudé <[email protected]>
Message-Id: <[email protected]>
Signed-off-by: Paolo Bonzini <[email protected]>

Author: bonzini

tests/docker/dockerfiles/fedora.docker

@@ -11,6 +11,7 @@ ENV PACKAGES \
     cyrus-sasl-devel \
     dbus-daemon \
     device-mapper-multipath-devel \
+    diffutils \
     findutils \
     gcc \
     gcc-c++ \