Forgive missing Packages files for new arches

Signed-off-by: Niels Thykier <niels@thykier.net>

britney.py

@@ -980,11 +980,21 @@ class Britney(object):
                 binary_dir = "binary-%s" % arch
                 filename = os.path.join(basedir,
                              component, binary_dir, 'Packages')
-                filename = possibly_compressed(filename)
+                try:
+                    filename = possibly_compressed(filename)
+                except FileNotFoundError as e:
+                    if arch not in self.options.new_arches:
+                        raise
+                    self.log("Ignoring missing file for new arch %s: %s" % (arch, filename))
                 udeb_filename =  os.path.join(basedir,
                                    component, "debian-installer",
                                               binary_dir, "Packages")
-                udeb_filename = possibly_compressed(udeb_filename)
+                try:
+                    udeb_filename = possibly_compressed(udeb_filename)
+                except FileNotFoundError as e:
+                    if arch not in self.options.new_arches:
+                        raise
+                    self.log("Ignoring missing file for new arch %s: %s" % (arch, udeb_filename))
                 self._read_packages_file(filename, arch,
                       self.sources[distribution], packages)
                 self._read_packages_file(udeb_filename, arch,