fixes #7850 - pin mixlib-shellout for Ruby 1.8 compatibility

(cherry picked from commit 56e62d1295ab65e7deca27890ee69e1312ceca0a)

Conflicts:
	bundler.d/test.rb
fixes #7822 - forbid HTTPS requests with no client SSL certificate

(cherry picked from commit 52f0bacf26923826a9b112369d504972369b3cf0)