[library-web] always init html_images

[Frederic Peters <fpeters src gnome org>]

commit 68b44284f896a720491a1906e4b1deef2a432344
Author: Frédéric Péters <fpeters 0d be>
Date:   Sun Jan 14 09:39:48 2018 +0100

    always init html_images

 src/modtypes/gtkdoc.py |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/src/modtypes/gtkdoc.py b/src/modtypes/gtkdoc.py
index 9bb669c..7989daf 100644
--- a/src/modtypes/gtkdoc.py
+++ b/src/modtypes/gtkdoc.py
@@ -52,6 +52,7 @@ class GtkDocModule(DocModule):
         doc_module = self.modulename
         ext_dirname = os.path.join(app.config.private_dir, 'extracts')
 
+        html_images = []
         if self.meson_build:
             main_sgml_file = None  # will force external HTML
         else:
@@ -62,7 +63,7 @@ class GtkDocModule(DocModule):
             try:
                 html_images = re.findall('HTML_IMAGES\s+=\s+(.*)', self.makefile_am)[0].split()
             except IndexError:
-                html_images = []
+                pass
             html_images = [x.replace('$(srcdir)/', '') for x in html_images]
 
         web_output_dir = app.get_module_web_output_dir(self)