Make the installation/uninstallation of Info pages follow the

Make the installation/uninstallation of Info pages follow the
regular am/recursive scheme.
* automake.in (%required_targets, %dependencies): Add
install-info.
(%dependencies): Add install-info, install-info-am, and
unstall-info.
(&handle_subdirs): Don't transform INSTALLINFO, which mapping was
reversed BTW.  Does anybody use the option `no-installinfo'?
(&handle_merge_targets): Let the handling of info related targets
to...
(&handle_factored_dependencies): this.
* subdirs.am: Use ?INSTALL-INFO?.
* texinfos.am: Define the install-info, uninstall-info and
uninstall-info-am targets.