Revert "The earlier commit ea119211b21 removed 'dsa' as one of the ssh_host_*_key"

Revert "The earlier commit ea119211b21 removed 'dsa' as one of the ssh_host_*_key"

The author (@pprindeville) of the original commit noted that the wrong
commit was picked, see
https://github.com/openwrt/packages/commit/325b7d2cd2d6e9d4903c6e7628c7c9ae0ddab564#commitcomment-22387528
"Err... looks like the wrong fix got committed. I was hoping that this
commit d902e5d would have gone in instead."

This reverts commit 325b7d2cd2d6e9d4903c6e7628c7c9ae0ddab564.

Signed-off-by: Daniel Golle <daniel@makrotopia.org>