remove Makefile target install-info-debian, modify install-info to be compatible

* Makefile: remove target install-info-debian and modify target
  install-info so that it is compatible with the older dpkg version
  of install-info that resides in /usr/sbin and may be picked up
  when root is installing info files

Initial reporting by Jude DaShiell, suggestions for changing Makefile
by Nick Dokos.  The solution implemented re-arranges the arguments to
install-info to be compatible with both the dpkg and GNU version of
the program.  On Debian, /usr/bin/install-info is actually a wrapper
that calls /usr/bin/ginstall-info and issues the following warning
when called as root:

This is not dpkg install-info anymore, but GNU install-info
See the man page for ginstall-info for command line arguments

This warning can be safely ignored since we actually prefer that GNU
install-info is called even though we've arranged the arguments to
be compatible with dpkg install-info.

Tested on openSuSE Tumbleweed, Win7/Pro (both MSys and Cygwin) and by
Jude DaShiell on Debian Squeeze and Slackware.

TINYCHANGE

Makefile

@@ -222,9 +222,6 @@ install-lisp: $(LISPFILES) $(ELCFILES)
 install-info: $(INFOFILES)
 	if [ ! -d $(infodir) ]; then $(MKDIR) $(infodir); else true; fi ;
 	$(CP) $(INFOFILES) $(infodir)
-	$(INSTALL_INFO) --info-file=$(INFOFILES) --info-dir=$(infodir)
-
-install-info-debian: $(INFOFILES)
 	$(INSTALL_INFO) --infodir=$(infodir) $(INFOFILES)
 
 autoloads: lisp/org-install.el

doc/org.texi

@@ -880,15 +880,21 @@ make install
 @end example
 
 Installing Info files is system dependent, because of differences in the
-@file{install-info} program.  In Debian it copies the info files into the
-correct directory and modifies the info directory file.  In many other
-systems, the files need to be copied to the correct directory separately, and
-@file{install-info} then only modifies the directory file.  Check your system
-documentation to find out which of the following commands you need:
+@file{install-info} program.  The following should correctly install the Info
+files on most systems, please send a bug report if not@footnote{The output
+from install-info (if any) is also system dependent.  In particular Debian
+and it's derivatives use two different versions of install-info and you may
+see the message:
+
+@example
+This is not dpkg install-info anymore, but GNU install-info
+See the man page for ginstall-info for command line arguments
+@end example
+
+@noindent which can be safely ignored.}.
 
 @example
 make install-info
-make install-info-debian
 @end example
 
 Then add the following line to @file{.emacs}.  It is needed so that