auth-token with auth-nocache fix broke --disable-crypto builds

auth-token with auth-nocache fix broke --disable-crypto builds

After adding commit 571165360db0392fa83e, it broke builds where
the --disable-crypto was used with ./configure.  This was due to
the delayed_auth_pass_purge() which requires the crypto code paths
being called from init.c without the proper #ifdef encapsulation.

Signed-off-by: David Sommerseth <davids@openvpn.net>
Acked-by: Gert Doering <gert@greenie.muc.de>
Message-Id: <20170619130507.13892-1-davids@openvpn.net>
URL: https://www.mail-archive.com/openvpn-devel@lists.sourceforge.net/msg14883.html
Signed-off-by: David Sommerseth <davids@openvpn.net>
(cherry picked from commit 5bde5b6d1875fd87b116c943084df0d2f6aee6d0)