BUG/MEDIUM: ssl: cache doesn't release shctx blocks

Since the rework of the shctx with the hot list system, the ssl cache
was putting session inside the hot list, without removing them.
Once all block were used, they were all locked in the hot list, which
was forbiding to reuse them for new sessions.

Bug introduced by 4f45bb9 ("MEDIUM: shctx: separate ssl and shctx")

Thanks to Jeffrey J. Persch for reporting this bug.

Must be backported to 1.8.
1 file changed