[tz] [PATCH] tzdata: Asia/Ha_Noi: Add new timezone

[Paul Eggert]

Thank you for this new information.  Since Hanoi and Ho Chi Minh City 
disagree for time stamps as late as 1975, we need to add a Zone for Hanoi.

The real jewel here is the indirect reference to the authoritative 
source"Lịch Việt Nam: thế kỉ XX–XXI (1901–2100) & Niên Biểu Lịch Sử Việt 
Nam" (2014) 
<http://bookaholic.vn/lich-viet-nam-the-ki-xx-xxi-1901-2100-va-bien-bieu-lich-su-viet-nam/>.  
I'd like to verify the information from this source if possible.  For 
example, if I'm reading the website correctly the 1906 transition was on 
July 1, not June 9, but I'd like to check that against the book.  I have 
requested a copy of the book from my library; it has a 2005 edition, 
which should suffice for our needs.

This underscores the unreliability of our old source Shanks. We already 
knew Shanks was wrong for large swaths of the world in the 20th 
century.  Even so, it's surprisingly bad for a U.S. source like Shanks 
to get South Vietnam wrong in 1973. Wasn't Shanks reading the newspapers?