Patch to update_web_docs

[Jeffrey A Law]

  In message <Pine.LNX.4.32.0103150102470.17530-100000@kern.srcf.societies.cam.
ac.uk>you write:
  > Now texi2html on gcc.gnu.org has been upgraded to a more recent
  > version, it is desirable for onlinedocs generation to use that version
  > rather than a local gccadmin version.  The following has been tested
  > by regenerating onlinedocs with the modified update_web_docs; OK to
  > commit, replace update_web_docs as used by gccadmin with the patched
  > version, and remove gccadmin's own copy of texi2html?
Sounds great to me.
jeff