host: libncurses5-dev: yet another issue...

Starting in jessie/sid/saucy, dpkg -l now returns lib<pkg_name>:<deb_arch>
vs lib<pkg_name>

While fixing that, also add $ to grep to get exact package name.

Reported-by: Adrien Ferre <ferre.adrien@gmail.com>
Signed-off-by: Robert Nelson <robertcnelson@gmail.com>