Unfortunately MemProvider Init does not actually Init properly (#6692) (#6693)

* Unfortunately MemProvider Init does not actually Init properly

Worse all of its members are private and you cannot update them.
Simple fix copy it in to modules session.

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

* Fix misspelling

modules/session/virtual.go

@@ -5,6 +5,7 @@
 package session
 
 import (
+	"container/list"
 	"encoding/json"
 	"fmt"
 	"sync"
@@ -38,7 +39,7 @@ func (o *VirtualSessionProvider) Init(gclifetime int64, config string) error {
 	// This is only slightly more wrong than modules/setting/session.go:23
 	switch opts.Provider {
 	case "memory":
-		o.provider = &session.MemProvider{}
+		o.provider = &MemProvider{list: list.New(), data: make(map[string]*list.Element)}
 	case "file":
 		o.provider = &session.FileProvider{}
 	case "redis":