Current RDEPENDS are OK for "amb-get, amb-set, ..." utils,
but they are deprecated in favor of "ambctl". This one
depends on python-curses, thus add it to make it work.
Change-Id: Ibbc8d0a0c71c68cdf3315c9fe86f8e257dc8ebff Signed-off-by: Manuel Bachmann <mbc@iot.bzh>