BUG/MEDIUM: ssl: force a full GC in case of memory shortage

When memory becomes scarce and openssl refuses to allocate a new SSL
session, it is worth freeing the pools and trying again instead of
rejecting all incoming SSL connection. This can happen when some
memory usage limits have been assigned to the haproxy process using
-m or with ulimit -m/-v.

This is mostly an enhancement of previous fix and is worth backporting
to 1.5.
(cherry picked from commit fba03cdc5ac6e3ca318b34915596cbc0a0dacc55)
1 file changed