I've heard that, but assumed it came from splitting up the name as "Postgre"+"SQL"; if you leave off the SQL part you get a word ending in E, and "postgreh" can't be right, can it? :)
Which is why I've also heard developers that either assumed the 'g' was silent or a transposition problem and you get "poster SQL", "postreg SQL", or worst of all "posgret SQL".
Somewhere, I believe in an HN comment, I saw a Postgres developer say that one of the biggest regrets of the project naming was capitalizing that "shared S".
