removed config.ssh settings

[Tobias Munk]

According to berkshelf/berkshelf#856

I replaced in Vagrantfile

config.ssh.max_tries = 40
config.ssh.timeout   = 120

with

config.vm.boot_timeout = 120

PS: Thanks for the cookbook so far, I haven't send you a PR, because I am fairly new to Vagrant & Co.

[Raúl Rodríguez]

Thanks for pointing it out. I've just fixed it in master :)