Open the HTML file in your favorite text editor and do a simple find and replace. If you are comfortable with a straight single quote, just find <92> and replace with ' and just hit find and replace all. Save the file and then run it through Calibre.
If you want a curled left quote, replace the <92> with "& # 1 4 6 ;" (without the quotes, and remove the spaces between the characters that I included) and you should be good to go.
For a handy table of HTML codes for various extended ASCII characters, go here.