[SECURITY] Fedora 25 Update: varnish-5.0.0-5.fc25

This is Varnish Cache, a high-performance HTTP accelerator. Varnish Cache stores web pages in memory so web servers don’t have to create the same web page over and over again. Varnish Cache serves pages much faster than any application server; giving the website a significant speed up. Documentation wiki and additional information about Varnish Cache is available on: https://www.varnish-cache.org/