Pass duplicate flag to SNI Initial Handler Callback

Summary: LibEventServer's SNI handling is primitive and requires a separate file per Subject Alt Name, but a server could load all the SAN's from the first callback invocation for a given cert.  Pass a flag that indicates whether the callback has already been invoked on the same underlying cert.

Reviewed By: @markw65

Differential Revision: D1462765
help git out by marking non-utf8 files

Summary: This came up when @swtaarrs had a diff which didn't apply. the `.diff` file from github thought it was a text file and issued a non-utf8 file which we couldn't `json_encode` it without mangling it.

I made this with:

  for f in `find . -type f`; do iconv -f utf8 $f > /dev/null 2>&1; if [ $? -ne 0 ]; then echo $f -diff >> .gitattributes; fi; done

Reviewed By: @JoelMarcey

Differential Revision: D1463749