Automatically remove obsolete source packages from testing.

An "obsolete source" is one which produces no binaries.  This situation
generally arises when all of the binaries which used to be produced by
the source package are now built by other sources.

Sooner or later such sources will probably be auto-crufted from unstable,
but there's no real reason to keep them in testing in the meantime.

Signed-off-by: Adam D. Barratt <adam@adam-barratt.org.uk>

britney.py

@@ -2408,6 +2408,17 @@ class Britney:
         if not self.options.compatible or self.options.autohinter:
             self.auto_hinter()
 
+        # obsolete source packages  
+        if not self.options.compatible:
+            self.__log("> Removing obsolete source packages from testing", type="I")
+            removals = []
+            sources = self.sources['testing']
+            removals = [ HintItem("-%s/%s" % (source, sources[source][VERSION])) for \
+                         source in sources if len(sources[source][BINARIES]) == 0 ]
+            if len(removals) > 0:
+                self.output_write("Removing obsolete source packages from testing (%d):\n" % (len(removals)))
+                self.do_all(actions=removals)
+                                                                                                                                     
         # smooth updates
         if not self.options.compatible and len(self.options.smooth_updates) > 0:
             self.__log("> Removing old packages left in testing from smooth updates", type="I")