Fix sdlcli get -command result stdout write

Fix sdlcli get -command result stdout write

Sdlcli get -command writes wrongly results to stderr stream. Fix sdlcli
get -command to write results to stdout stream when command execution
has succeeded. In addition add similar stdout redirect also to sdlcli
statistics -command just to keep the code look the same, even thought
there wasn't any real issue with sdlcli statistics -command's results
visibility.

Version: 0.9.3

Issue-Id: RIC-873

Signed-off-by: Timo Tietavainen <timo.tietavainen@nokia.com>
Change-Id: Icc7d42d9200bdcc74bf1da6ceab341dd6b69c16e