hurd: Don't migrate reply port into __init1_tcbhead

Properly differentiate between setting up the real TLS with
TLS_INIT_TP, and setting up the early TLS (__init1_tcbhead) in static
builds. In the latter case, don't yet migrate the reply port into the
TCB, and don't yet set __libc_tls_initialized to 1.

This also lets us move the __init1_desc assignment inside
_hurd_tls_init ().

Fixes cd019ddd
"hurd: Don't leak __hurd_reply_port0"

Signed-off-by: Sergey Bugaev <bugaevc@gmail.com>