openssh: Set ssh.service enabled instead of ssh.socket.
openssh: Set ssh.service enabled instead of ssh.socket.

In Debian 8, ssh.service is used by default.
ssh.socket is enabled when user wants to change port number of sshd.

Signed-off-by: Masahiro Yamada <76d6c03d331b29d77eaac66c3113243c4dd22703@toshiba.co.jp>

tienlee/meta-debian,meta-debian/meta-debian,meta-debian/meta-debian,meta-debian/meta-debian,tienlee/meta-debian,nghiaht-tsdv/meta-debian,nghiaht-tsdv/meta-debian,nghiaht-tsdv/meta-debian,meta-debian/meta-debian,nghiaht-tsdv/meta-debian,nghiaht-tsdv/meta-debian,tienlee/meta-debian,meta-debian/meta-debian,tienlee/meta-debian,meta-debian/meta-debian,tienlee/meta-debian,nghiaht-tsdv/meta-debian,tienlee/meta-debian