[rygel] Fix the doc build when installing from the tarball

[Jens Georg <jensgeorg src gnome org>]

commit 354dd9db59d95bde6631aed30647a3ff8ed5baed
Author: Regis Merlino <regis merlino intel com>
Date:   Tue Nov 20 17:46:53 2012 +0100

    Fix the doc build when installing from the tarball
    
    https://bugzilla.gnome.org/show_bug.cgi?id=688409

 doc/reference/doc-build.am |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)
---
diff --git a/doc/reference/doc-build.am b/doc/reference/doc-build.am
index 6074a76..66f6317 100644
--- a/doc/reference/doc-build.am
+++ b/doc/reference/doc-build.am
@@ -55,8 +55,6 @@ clean-local:
 	rm -f gtkdoc/lib$(RYGEL_DOCBUILD_MODULE)*.txt
 	rm -f gtkdoc/lib$(RYGEL_DOCBUILD_MODULE).prerequisites
 
-RYGEL_GTKDOC_INSTALL_DIR = $(DESTDIR)$(datadir)/gtk-doc/html/lib$(RYGEL_DOCBUILD_MODULE)
-
 uninstall-hook:
 	rm -rf $(INSTALL_DIR)
 
@@ -64,6 +62,8 @@ all: valadoc-gen gtkdoc-gen
 
 endif
 
+RYGEL_GTKDOC_INSTALL_DIR = $(DESTDIR)$(datadir)/gtk-doc/html/lib$(RYGEL_DOCBUILD_MODULE)
+
 # The chmod corrects the directory permissions so that distcheck can remove the installed files.
 install-data-hook: gtkdoc/html/index.html
 	$(MKDIR_P) $(RYGEL_GTKDOC_INSTALL_DIR)