* When reading expired sessions - expire them

Update to latest macaron/session following merge of
https://gitea.com/macaron/session/pulls/11

Also remove old memory provider as 11 updates the memory provider to
make it unnecessary.

Signed-off-by: Andrew Thornton <art27@cantab.net>

* and macaron/session/pulls/12

Signed-off-by: Andrew Thornton <art27@cantab.net>

Co-authored-by: zeripath <art27@cantab.net>

Signed-off-by: Tamal Saha <tamal@appscode.com>