[gegl] Don't try to install gegl.devhelp if ruby isn't present.

[Michael Murà <mmure src gnome org>]

commit 0c087d4274275dbdc580af3b6186c444a64122cb
Author: Michael Henning <mikehenning eclipse net>
Date:   Mon Mar 26 19:44:52 2012 -0400

    Don't try to install gegl.devhelp if ruby isn't present.
    
    gegl.devhelp is generated by tools/create-reference.rb
    Without ruby we should not attempt to install it.

 docs/Makefile.am |    5 ++---
 1 files changed, 2 insertions(+), 3 deletions(-)
---
diff --git a/docs/Makefile.am b/docs/Makefile.am
index d2be336..8f1f3ec 100644
--- a/docs/Makefile.am
+++ b/docs/Makefile.am
@@ -14,12 +14,11 @@ HTML_FILES = \
 
 GTKDOC_FILES = \
 	operations.html		\
-	gegl.css			\
-	gegl.devhelp
+	gegl.css
 
 if HAVE_RUBY
 HTML_FILES += api.html images/inheritance.png
-GTKDOC_FILES += api.html
+GTKDOC_FILES += api.html gegl.devhelp
 endif
 
 gegl.devhelp: api.html