development/fsharp: Fix build failure.
development/fsharp: Fix build failure.

'mozroots' is deprecated, and recently stopped working.
The replacement is 'cert-sync', see:
http://www.mono-project.com/docs/about-mono/releases/3.12.0/

Signed-off-by: David Spencer <6fdd2e767cd80a090a42bdb678c4a4cd6a53629b@googlemail.com>

panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds,panosmdma/SlackOnly-SlackBuilds