(MODULES-4819) remove include_src parameter from vhost_spec

include_src is no longer a parameter in apt::source, which is used in vhost_spec as part of the fastcgi test. Instead, include is now a hash with keys 'deb' and 'src'. 'src' defaults to false as of apt 4.0.0 so I removed include_src altogether with no replacement

spec/acceptance/vhost_spec.rb

@@ -1589,21 +1589,18 @@ class { 'apache': }
             location    => $_location,
             release     => $_release,
             repos       => $_repos,
-            include_src => false,
           }
 
           apt::source { "${_os}_${_release}-updates":
             location    => $_location,
             release     => "${_release}-updates",
             repos       => $_repos,
-            include_src => false,
           }
 
           apt::source { "${_os}_${_release}-security":
             location    => $_security_location,
             release     => $_release_security,
             repos       => $_repos,
-            include_src => false,
           }
         EOS