Remove comments regarding former requirements

Don't explain why Libtool and Gettext are no longer needed.  Libtool
actually is a requirement, as (at least) the M4 macros provided by
Libtool are needed for our Autotools setup.  And the fact that Gettext
is no longer needed probably isn't that interesting for new developers.

Signed-off-by: Holger Weiss <holger@zedat.fu-berlin.de>

doc/developer-guidelines.sgml

@@ -69,14 +69,6 @@
 	make install
 	</literallayout>
 	</para>
-
-	<para>Note: gettext is no longer a developer platform requirement. A lot of the files in lib/ and m4/
-	are synced with the coreutils project and we use the same levels of gettext that they
-	distribute.
-	</para>
-	<para>Note: gnu libtool, which must be at version 1.5.22 or above, has files installed into CVS, so is not 
-	a development platform requirement.
-	</para>
 </section>
 
 <section id="PlugOutput"><title>Plugin Output for Nagios</title>