Add new argument "add_env=FOO,BAR,KRB5CCNAME" to pam_escalate.so which saves
process environment variables to PAM environment variables that aren't set.
Make pam_sm_setcred return PAM_SUCCESS like it's supposed to so pam_setcred
doesn't return PAM_PERM_DENIED.
Merge pull request #12 from google/vonhollen-dev

Fix Kerberos credential refreshes under pam_escalate.so and apps like gnome-screensaver.