lib/oe/terminal: set workdir for konsole terminal

lib/oe/terminal: set workdir for konsole terminal

It seems that if the --workdir option is not set konsole does open in the users
home directory. By setting --workdir . konsole opens in the recipes work
directory. This is the same behavior as observed for other consoles.
(Tested with Konsole 2.14.2 on Debian Jessie).

Signed-off-by: Pascal Bach <pascal.bach@siemens.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>