Generate sphinx's conf.py to embed version number

The sphinx configuration includes the version number, so generate the
configuration.

configure.ac

@@ -503,6 +503,7 @@ AC_CONFIG_FILES([
     bin/varnishtop/Makefile
     doc/Makefile
     doc/sphinx/Makefile
+    doc/sphinx/conf.py
     etc/Makefile
     include/Makefile
     lib/Makefile

doc/sphinx/conf.py → doc/sphinx/conf.py.in

@@ -45,9 +45,9 @@ copyright = u'2010, Varnish Project'
 # built documents.
 #
 # The short X.Y version.
-version = '-trunk'
+version = '@VERSION@'
 # The full version, including alpha/beta/rc tags.
-release = '-trunk'
+release = '@VERSION@'
 
 # The language for content autogenerated by Sphinx. Refer to documentation
 # for a list of supported languages.
@@ -130,7 +130,7 @@ html_theme_options = {
 
 # The name for this set of Sphinx documents.  If None, it defaults to
 # "<project> v<release> documentation".
-#html_title = None
+html_title = "Varnish version @VERSION@ documentation"
 
 # A shorter title for the navigation bar.  Default is the same as html_title.
 #html_short_title = None