Bug#1064744: glib-networking: System trust contains zero trusted certificates

[Jeremy Bícha]

Alessandro figured out that although the Debian buildds have
ca-certificates installed, the default sbuild configuration for
Unstable does not pull it in. Therefore, we will fix this issue by
simply adding ca-certificates to Build-Depends for affected packages.

It seems odd that there is this mismatch in installed packages though.

Thank you,
Jeremy Bícha