Create fake revisions for every commit in the base of a linked package

This is a rather complex operation, but whenever a package changes in
Factory, the inherited package gets a shadow revision consisting of the
3-way merge. If this happens due to a request being accepted, this is
actually in most cases also commited by 'buildservice-autocommit',
so we're making sure this is always happening (and are actually
duplicating revisions in cases that we filter out later as empty
commits).

To differenciate the fake revisions from the real revisions, I add
a fraction part

lib/exporter.py

@@ -13,7 +13,10 @@ class Exporter:
     def run(self):
         db = DB()
         cur = db.cursor()
-        cur.execute("SELECT * from revisions where package=%s", (self.package,))
+        cur.execute(
+            "SELECT * from revisions where package=%s ORDER BY project,rev",
+            (self.package,),
+        )
         data = {"revisions": []}
         for row in cur.fetchall():
             data["revisions"].append(DBRevision(row).as_dict(db))