DOCX Input: Fix error when converting DOCX file that contains only image based links and no text based links. Fixes #1263021 [Book failed to convert docx to ePub](https://bugs.launchpad.net/calibre/+bug/1263021)

src/calibre/ebooks/docx/images.py

@@ -184,7 +184,7 @@ class Images(object):
                     img = IMG(src='images/%s' % src)
                     img.set('alt', alt or 'Image')
                     if link is not None:
-                        self.links.append((img, link))
+                        self.links.append((img, link, self.rid_map))
                     return img
 
     def drawing_to_html(self, drawing, page):

src/calibre/ebooks/docx/to_html.py

@@ -516,7 +516,7 @@ class Convert(object):
                     continue
                 span.set('href', url)
 
-        for img, link in self.images.links:
+        for img, link, relationships_by_id in self.images.links:
             parent = img.getparent()
             idx = parent.index(img)
             a = A(img)