Remove session lock as it's worthless now that PWD is deployed in (#204)

multiple servers

pwd/instance.go

@@ -97,8 +97,6 @@ func (p *pwd) InstanceDelete(session *types.Session, instance *types.Instance) e
 
 func (p *pwd) InstanceNew(session *types.Session, conf types.InstanceConfig) (*types.Instance, error) {
 	defer observeAction("InstanceNew", time.Now())
-	session.Lock()
-	defer session.Unlock()
 
 	instances, err := p.storage.InstanceFindBySessionId(session.Id)
 	if err != nil {

pwd/types/session.go

@@ -1,7 +1,6 @@
 package types
 
 import (
-	"sync"
 	"time"
 )
 
@@ -16,13 +15,4 @@ type Session struct {
 	ImageName    string    `json:"image_name" bson:"image_name"`
 	Host         string    `json:"host" bson:"host"`
 	UserId       string    `json:"user_id" bson:"user_id"`
-	rw           sync.Mutex `json:"-"`
-}
-
-func (s *Session) Lock() {
-	s.rw.Lock()
-}
-
-func (s *Session) Unlock() {
-	s.rw.Unlock()
 }