bridge: Rewrite dbus-daemon setup using GSubprocess
bridge: Rewrite dbus-daemon setup using GSubprocess

g_subprocess_launcher_take_fd() avoids a custom child setup function,
and we can use a static fd assignment in the subprocess for
--print-address.

Use g_auto(), which gets rid of all `goto`s. Move local variable
declaration to their first assigment, which simplifies the code a bit.

mvollmer/cockpit,mvollmer/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,martinpitt/cockpit,mvollmer/cockpit,martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit