The posix_spawnattr_tcsetpgrp_np works on a file descriptor (the
controlling terminal), so it would make more sense to actually fit
it on the file actions API.
Also, POSIX_SPAWN_TCSETPGROUP is not really required since it is
implicit by the presence of tcsetpgrp file action.
The posix/tst-spawn6.c is also fixed when TTY can is not present.
Checked on x86_64-linux-gnu and i686-linux-gnu.
Reviewed-by: Carlos O'Donell <carlos@redhat.com>
Tested-by: Carlos O'Donell <carlos@redhat.com>
