bash->bourne script cleanup

bash->bourne script cleanup

Many of the scripts in the openvpn source have their shell set to
/bin/bash, but only two use bash features. The attached patch (against
openvpn-2.1_rc9) sets the shell on the rest of the scripts to /bin/sh for
better portability. The only scripts that actually require bash are
contrib/pull-resolv-conf/client.{up,down} ; they use the ${!var} variable
indirection feature.

sf.net tracker:
<https://sourceforge.net/tracker/?func=detail&aid=2040296&group_id=48978&atid=454721>

Discussed on the IRC meeting March 4, 2010 in #openvpn-discussions.
<http://thread.gmane.org/gmane.network.openvpn.devel/3242>

Signed-off-by: David Sommerseth <dazo@users.sourceforge.net>
Acked-by: James Yonan <james@openvpn.net>