libctf: do not crash when CTF symbol or variable linking fails

libctf: do not crash when CTF symbol or variable linking fails

When linking fails, we delete all the generated outputs, but we fail to
remove them from the ctf_link_outputs hash we stuck them in before doing
symbol and variable section linking (which we had to do because that's
where ctf_create_per_cu, used by both, looks for them).  This leaves
stale pointers to freed memory behind, and crashes soon follow.

Fix obvious.

libctf/ChangeLog
2020-11-20  Nick Alcock  <nick.alcock@oracle.com>

	* ctf-link.c (ctf_link_deduplicating): Clean up the ctf_link_outputs
	hash on error.