[library-web] ignore missing documentation tarballs

[Frederic Peters <fpeters src gnome org>]

commit 52e33b55dba36f145b919b9c2b37baec4a979a13
Author: Frédéric Péters <fpeters 0d be>
Date:   Sun Feb 11 11:47:37 2018 +0100

    ignore missing documentation tarballs

 src/modtypes/gtkdoc.py |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)
---
diff --git a/src/modtypes/gtkdoc.py b/src/modtypes/gtkdoc.py
index 146ab27..8bd5cba 100644
--- a/src/modtypes/gtkdoc.py
+++ b/src/modtypes/gtkdoc.py
@@ -135,6 +135,9 @@ class GtkDocModule(DocModule):
                                 logging.debug('extracting %s' % tarball_location)
                                 os.makedirs(htmlfiles_dir)
                                 doc_tarball = app.download(tarball_location)
+                                if not doc_tarball:
+                                    logging.error('skipped %s as it is missing a doc tarball' % doc_module)
+                                    return
                                 tar2 = tarfile.open(doc_tarball, 'r')
                                 ext2_dirname = os.path.join(ext_dirname, 'doc-tarballs', 
self.dirname.split('/')[0])
                                 for tar2info in tar2.getmembers():