Ensure socache_shmcb is enabled on all Apache 2.4 OSes

The SSLSessionCache option is specified as socache_shmcb, so the module must
be enabled.
Merge pull request #612 from domcleal/f19-ssl

Ensure socache_shmcb is enabled on all Apache 2.4 OSes
Add WSGIApplicationGroup and WSGIImportScript directives
Add WSGIApplicationGroup & WSGIImportScript tests.
More WSGI tests