BUG/MINOR: ssl: revert two wrong fixes with ckhi_link

BUG/MINOR: ssl: revert two wrong fixes with ckhi_link

This reverts commit 056ad01d55675ab2d65c7b41a2e1096db27b3d14.
This reverts commit ddd480cbdc0d54b3426ce9b6dd68cd849747cb07.

The architecture is ambiguous here: ckch_inst_free() is detaching and
freeing the "ckch_inst_link" linked list which must be free'd only from
the cafile_entry side.

The problem was also hidden by the fix ddd480c ("BUG/MEDIUM: ssl: Fix a
UAF when old ckch instances are released") which change the ckchi_link
inner loop by a safe one. However this can't fix entirely the problem
since both __ckch_inst_free_locked() could remove several nodes in the
ckchi_link linked list.

This revert is voluntary reintroducing a memory leak before really fixing
the problem.

Must be backported in 2.5 + 2.6.