Bug fix for timestamptz datatype (insert throws an error when year field len > 4 for timestamptz datatype)

https://commitfest.postgresql.org/action/patch_view?id=1193
http://archives.postgresql.org/message-id/CAGPqQf3XwWC_4fhiNz_G6EcvPs_OV3k2pe4-aJ1dg4iyY+f_Dw@mail.gmail.com