elf: Signal RT_CONSISTENT after relocation processing in dlopen (bug 31986)

elf: Signal RT_CONSISTENT after relocation processing in dlopen (bug 31986)

Previously, a la_activity audit event was generated before
relocation processing completed.  This does did not match what
happened during initial startup in elf/rtld.c (towards the end
of dl_main).  It also caused various problems if an auditor
tried to open the same shared object again using dlmopen:
If it was the directly loaded object, it had a search scope
associated with it, so the early exit in dl_open_worker_begin
was taken even though the object was unrelocated.  This caused
the r_state == RT_CONSISTENT assert to fail.  Avoidance of the
assert also depends on reversing the order of r_state update
and auditor event (already implemented in a previous commit).

At the later point, args->map can be NULL due to failure,
so use the assigned namespace ID instead if that is available.

Reviewed-by: Adhemerval Zanella <adhemerval.zanella@linaro.org>