symbiosis-httpd-configure breaks when no certificates are available.

[ianeiloart]

symbiosis-httpd-configure breaks when no certificates are available.

Steps to reproduce:

1. Spin up a new Symbiosis 8 server at panel.bytemark.co.uk
2. remove the contents of /etc/ssl
3. run "symbiosis-httpd-configure --force --verbose"
4. run "apachectl restart"

Expected behaviour:
Apache restarts.
Observed behaviour:
Apache fails to restart. An error message like "Failed to configure at least one certificate and key for symbiosis.foo.bar.uk0.bigv.io:443"

Workaround:
remove /etc/apache2/sites-enabled/zz-mass-hosting.ssl.conf - Apache will now start, until symbiosis-httpd-configure is run again.

Suggested fix:
Symbiosis-httpd-configure should test for the presence of some certificate before proceeding to enable zz-mass-hosting.ssl.conf

[DavidGoodwin]

Thanks for creating the issue @ianeiloart