gdata: Fix typo

All the arguments were off by one. Pass NULL for graph because that is
what we are using for folders.

https://bugzilla.gnome.org/show_bug.cgi?id=694003
gdata: Link folders and their children correctly

We should use GDATA_LINK_SELF as nao:identifier for folders instead of
GDataEntry:id, because that is how gdata_entry_look_up_links
identifies the parent folder of a child.

https://bugzilla.gnome.org/show_bug.cgi?id=694003
gdata: Create a graph based on the nie:dataSource

Looks like we have to force a full reindex of Google resources to make
sure folders are correctly linked to their children. We can take this
opportunity to fix the use graphs in this miner.

https://bugzilla.gnome.org/show_bug.cgi?id=694003
gdata: Force full reindex

https://bugzilla.gnome.org/show_bug.cgi?id=694003