launch-client: Print version number, --bus-name to original stdout
These were intended to be written to the original stdout, but we didn't do that until after we'd already replaced stdout with stderr to avoid random diagnostic messages appearing on the original stdout.
To reproduce:
.../pressure-vessel/bin/steam-runtime-launch-client --version | sed -e 's/^/STDOUT:/'
.../pressure-vessel/bin/steam-runtime-launch-client --list | sed -e 's/^/STDOUT:/'
Expected result: the version information and the list of bus names come out on stdout, go into the pipe and get prefixed with STDOUT:
by sed
Actual result: the version information and the list of bus names come out on stderr and bypass the pipe to sed