gnus-faq.texi, gnus.texi: Port documentation to Texinfo 5.0
* gnus-registry.el (gnus-registry-save): Provide class name when
  calling `eieio-persistent-read' to avoid "unsafe call" warning.  Use
  `condition-case' to stay compatible with older EIEIO versions which
  only accept one argument.
Silence byte compiler.

(gnus-registry-read): Wrap call to `eieio-persistent-read' with two
arguments in `with-no-warnings', so that older Emacsen don't complain
during byte compilation.