BUG/MINOR: ssl/cli: duplicate cleaning code in cli_parse_del_crtlist

BUG/MINOR: ssl/cli: duplicate cleaning code in cli_parse_del_crtlist

Since 23cab33 ("BUG/MINOR: ssl: Clear the ckch instance when deleting a
crt-list line"), LIST_DELETE is done twice, one time in
cli_parse_del_crtlist() and another time in ckch_inst_free().

It could trigger a crash with -DDEBUG_LIST.

This isn't a major problem since the ptr is not freed in the meantime so
it will only trigger with the debug.

This patch removes the LIST_DELETE as well as the loop done on link_ref
which is also don in ckch_inst_free()

Could be backported as far as 2.4. 2.4 version does not have a link_ref
loop.