In case the lxc command socket is hashed and the socket was created for a
different path than the one we're currently querying
lxc_cmd_get_{lxcpath,name}() can return NULL. The command socket path is hashed
when len(lxcpath) > sizeof(sun_path) - 2.
Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>