binutils: doc: remove stale things from Makefile

binutils: doc: remove stale things from Makefile

The `install-data-local: install-info` part: the comment refers to when
the Makefile had the cygnus option.  It no longer uses that, so the info
file should get installed without that rule.  I verified that `make
install` still installed $(prefix)/share/info/binutils.info.

The `DISTCLEANFILES` part: the comment talks about Automake 1.9, we are
using 1.15.1, which doesn't appear to have this problem.  binutils.info
is built fine without this snippet.

Note: with my automake 1,15.1 (built from source), I get a spurious diff
in Makefile.in, where the

  runstatedir = @runstatedir@

line gets removed.  I am not sure why, but I haven't included it.

binutils/ChangeLog:

	* doc/Makefile.am (install-data-loca): Remove target.
	(DISTCLEANFILES): Remove variable.
	* doc/Makefile.in: Re-generate.