oeqa/utils/qemurunner: replace hard-coded user 'root' in debug output

oeqa/utils/qemurunner: replace hard-coded user 'root' in debug output

Since login user is configurable with boot_patterns['send_login_user'],
unconditionally using 'root' in the debug message can be confusing.

Also fix the debug message to say 'Logged in' instead of 'Logged'.

Signed-off-by: Enrico Jorns <ejo@pengutronix.de>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
(cherry picked from commit 900e3d42b918b5a33d8d952b3a8078fbe72ba98f)
Signed-off-by: Steve Sakoman <steve@sakoman.com>