*_radius(s): doc: update to the new doc makefile format

Update the doc makefiles for auth_radius, avp_radius and
uri_radius.

modules_s/auth_radius/doc/Makefile

@@ -1,29 +1,4 @@
-#
-# The list of documents to build (without extensions)
-#
-DOCUMENTS = auth_radius
+docs = auth_radius.xml
 
-#
-# The root directory containing Makefile.doc
-#
-ROOT_DIR=../../..
-
-#
-# Validate docbook documents before generating output
-# (may be slow)
-#
-#VALIDATE=1
-
-#
-# You can override the stylesheet used to generate
-# xhtml documents here
-#
-#XHTML_XSL=$(ROOT_DIR)/doc/stylesheets/xhtml.xsl
-
-#
-# You can override the stylesheet used to generate
-# plain text documents here
-#
-#TXT_XSL=$(XHTML_XSL)
-
-include $(ROOT_DIR)/Makefile.doc
+docbook_dir=../../../docbook
+include $(docbook_dir)/Makefile.module

modules_s/avp_radius/doc/Makefile

@@ -1,29 +1,4 @@
-#
-# The list of documents to build (without extensions)
-#
-DOCUMENTS = avp_radius
+docs = avp_radius.xml
 
-#
-# The root directory containing Makefile.doc
-#
-ROOT_DIR=../../..
-
-#
-# Validate docbook documents before generating output
-# (may be slow)
-#
-#VALIDATE=1
-
-#
-# You can override the stylesheet used to generate
-# xhtml documents here
-#
-#XHTML_XSL=$(ROOT_DIR)/doc/stylesheets/xhtml.xsl
-
-#
-# You can override the stylesheet used to generate
-# plain text documents here
-#
-#TXT_XSL=$(XHTML_XSL)
-
-include $(ROOT_DIR)/Makefile.doc
+docbook_dir=../../../docbook
+include $(docbook_dir)/Makefile.module

modules_s/uri_radius/doc/Makefile

@@ -1,29 +1,4 @@
-#
-# The list of documents to build (without extensions)
-#
-DOCUMENTS = uri_radius
+docs = uri_radius.xml
 
-#
-# The root directory containing Makefile.doc
-#
-ROOT_DIR=../../..
-
-#
-# Validate docbook documents before generating output
-# (may be slow)
-#
-#VALIDATE=1
-
-#
-# You can override the stylesheet used to generate
-# xhtml documents here
-#
-#XHTML_XSL=$(ROOT_DIR)/doc/stylesheets/xhtml.xsl
-
-#
-# You can override the stylesheet used to generate
-# plain text documents here
-#
-#TXT_XSL=$(XHTML_XSL)
-
-include $(ROOT_DIR)/Makefile.doc
+docbook_dir=../../../docbook
+include $(docbook_dir)/Makefile.module