- fixed copyright header and removed obsolete comments about how to
  build the manual using texinfo
- added an "install-data-hook" to install the mysql.info info page.
  This seems to be the only way to install info pages, if they are not
  built from texinfo sources directly.


Docs/Makefile.am:
  - fixed copyright header and removed obsolete comments about how to
    build the manual using texinfo
  - added an "install-data-hook" to install the mysql.info info page.
    This seems to be the only way to install info pages, if they are not
    built from texinfo sources directly.