Record now assigned CVEs for chromium-browser issues

In meanwhile according to

https://chromereleases.googleblog.com/2018/09/stable-channel-update-for-desktop_11.html

two CVEs were assigned for the issues fixed in DSA-4297-1

 - CVE-2018-17458: Function signature mismatch in WebAssembly.
 - CVE-2018-17459: URL Spoofing in Omnibox