fix: set SessionOn always true (#877)

* fix: set SessionOn always true

* Update adapter.go

Co-authored-by: Gucheng <85475922+nomeguy@users.noreply.github.com>

conf/app.conf

@@ -1,7 +1,6 @@
 appname = casdoor
 httpport = 8000
 runmode = dev
-SessionOn = true
 copyrequestbody = true
 driverName = mysql
 dataSourceName = root:123456@tcp(localhost:3306)/

conf/conf_test.go

@@ -79,13 +79,9 @@ func TestGetConfBool(t *testing.T) {
 		input       string
 		expected    interface{}
 	}{
-		{"Should be return false", "SessionOn", false},
 		{"Should be return false", "copyrequestbody", true},
 	}
 
-	//do some set up job
-	os.Setenv("SessionOn", "false")
-
 	err := beego.LoadAppConfig("ini", "app.conf")
 	assert.Nil(t, err)
 	for _, scenery := range scenarios {