This changes all the puppet 3 validate_* functions
to use the validate_legacy function.
The validate_legacy function has been available since
about three years but require Puppet >= 4.4.0 and since
there is Puppet 4.10.12 as latest we should assume people
are running a fairly new Puppet 4 version.
This is the first step to then remove all validate function
calls and use proper types for parameter as described in spec [1].
[1] https://review.openstack.org/#/c/568929/
Change-Id: Ib21fef57404d63579743270be4080d248a4ca8cc
4b558f6f00