Previously, GetEnvParams (now called SetEnvParams) had no way of being altered unless
it was through enviroment variables. These changes allow for a global
EnvParam to be set and also altered while still initally getting their value from
set enviroment variables. This change is especially helpful for testing
(see kubeadm/app/util/kubeconfig_test.go).
Currently the boostrap fails when a token is provided by the user
on `master init` and works when the token is generated. This is
because of a mismatch of how the token string in the kube-discovery
secret is encoded.
