fix redis cache failed (#3086)

modules/setting/setting.go

@@ -1399,7 +1399,7 @@ func newSessionService() {
 	SessionConfig.Provider = Cfg.Section("session").Key("PROVIDER").In("memory",
 		[]string{"memory", "file", "redis", "mysql"})
 	SessionConfig.ProviderConfig = strings.Trim(Cfg.Section("session").Key("PROVIDER_CONFIG").MustString(path.Join(AppDataPath, "sessions")), "\" ")
-	if !filepath.IsAbs(SessionConfig.ProviderConfig) {
+	if SessionConfig.Provider == "file" && !filepath.IsAbs(SessionConfig.ProviderConfig) {
 		SessionConfig.ProviderConfig = path.Join(AppWorkPath, SessionConfig.ProviderConfig)
 	}
 	SessionConfig.CookieName = Cfg.Section("session").Key("COOKIE_NAME").MustString("i_like_gitea")