busybox

login: apply PAM environment

login should apply the PAM environment modified by plugins
such as pam_env.  Other 'login's do a similar thing.

I tested this by setting some env variables with pam_env which were
correctly applied.

Signed-off-by: Ian Wienand <ianw@vmware.com>
Signed-off-by: Denys Vlasenko <vda.linux@googlemail.com>