(#8858) Explicitly set SSL peer verification mode.

In Ruby 1.8 the Net::HTTP library defaults to skipping peer verification when
no mode is explicitly set. Ruby 1.9, on the other hand, does not: it defaults
to verification of the peer certificate - leading to failure when we depended
on the default value in our HTTP setup.

This changes to explicitly set the verification mode, ensuring we get
consistent results across all Ruby versions.

Signed-off-by: Daniel Pittman <daniel@puppetlabs.com>