[ironic] Stepping down from core

Hi ironic folks, I'm sorry for my long absence. My job responsibility changed last November. Since it, I have been trying to spend some time on the core activity. But, I couldn't. So, I'm stepping down from the ironic core team. Thank you for accepting me to the team even though I didn't often appear in IRC due to the time difference. I hope I will work with you again someday. Best regards, Hironori