facts: Require awk and cargo for libnbd

OpenSUSE Tumbleweed manages to install without awk by default, leading to this failure while building libnbd: #28 (closed) configure: creating ./config.status config.status: creating podwrapper.pl ./config.status: line 1496: awk: command not found

What's more, libnbd just recently gained support for Rust bindings, so it wants to include cargo by default during CI.

Signed-off-by: Eric Blake eblake@redhat.com