firefox regressions

USN-4546-1 fixed vulnerabilities in Firefox. The update introduced various
minor regressions. This update fixes the problem.

We apologize for the inconvenience.

Original advisory details:

Multiple security issues were discovered in Firefox. If a user were
tricked in to opening a specially crafted website, an attacker could
potentially exploit these to cause a denial of service, conduct cross-site
scripting (XSS) attacks, spoof the site displayed in the download dialog,
or execute arbitrary code.