openssl: SSH command returns "Segmentation fault" on AMD64 (Bug #345)

The current version of openssl used in VyOS causes a segmentation fault
when either the SSH service is enabled, with the result that no host
keys are generated, and so the service won't start, or SSH is used from
the CLI.  This has been caused by a change in the ABI due ti compiler
options used for AMD64 builds.

This commit fixes the AMD64 build, based on a patch from Debian Squeeze

Bug #345 http://bugzilla.vyos.net/show_bug.cgi?id=345
openssl: add dh_gencontrol to enable development builds

Add VyOS based dh_gencontrol settings to debian/rules to enable
development builds (999.dev).  Due to a limitation in debhelper, this
also requires the debhelper_udeb_gencontrol.patch from build-iso/tools
to be applied against the build environment, but only for building
development versions.
0.9.8zc+vyos2+lithium4