vyatta-cfg-vpn: fix for vti interface going down remains routed

Revert the fix put in place for Bug #183 as this causes multiple routes
to be installed when more than one VTI routes to the same subnet (in
the case of failure over routing etc).  As it stands, when one of these
interfaces goes down, the additional route remains active, resulting in
this route still being used even though no traffic can pass.

Removing the up-client fix proposed for Bug #183 fixes this issue and
doesn't affect the normal operation of these VTIs.

Bug #291 http://bugzilla.vyos.net/show_bug.cgi?id=291
vyatta-cfg-vpn: rename vti-up-down.sh to vti-up-down

Rename vti-up-down.sh to vti-up-down to be consistent with others.
vyatta-cfg-vpn: formatting changes for style consistency

Update scripts/vpn-config.pl to have consistent identation levels and
style throughout.
vyatta-cfg-vpn: prevent duplicate local rsa key includes

Prevent duplicate include statements, for the local rsa keys, being
added to the ipsec.secrets file when more than one VPN connection is
configured.

Bug #332 http://bugzilla.vyos.net/show_bug.cgi?id=332