lang/ruby2*: disable dtrace on OS versions without the dtrace fixes from r271413

While here, fix plist issues


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@372456 35697150-7ecd-e111-bb59-0022644237b5
Fix build as a user.

Sponsored by:	Absolight


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@372457 35697150-7ecd-e111-bb59-0022644237b5
Add a missing dependency for the latest Flash plugin.

Reported by:	Piotr Kubaj (pkubaj at riseup dot net)


git-svn-id: svn+ssh://svn.freebsd.org/ports/head@372458 35697150-7ecd-e111-bb59-0022644237b5