Merge ~robru/britney/+git/britney2-ubuntu:fix-traceback into ~ubuntu-release/britney/+git/britney2-ubuntu:master

[Robert Bruce Park]

Stops returning None from a function where the caller expects strings.

And also round the age since people complained about that.

[Steve Langasek (vorlon)]

review: Approve

diff --git a/britney2/policies/email.py b/britney2/policies/email.py
index f335064..129d665 100644
--- a/britney2/policies/email.py
+++ b/britney2/policies/email.py
@@ -31,7 +31,7 @@ Hi,
 
 {source_name} {version} needs attention.
 
-It has been stuck in {series}-proposed for {age} day{plural}.
+It has been stuck in {series}-proposed for {age:.0f} day{plural}.
 
 You either sponsored or uploaded this package, please investigate why it hasn't been approved for migration.
 
@@ -64,14 +64,14 @@ def person_chooser(source):
 
 def address_chooser(addresses):
     """Prefer @ubuntu and @canonical addresses."""
-    first = None
-    canonical = None
+    first = ''
+    canonical = ''
     for address in addresses:
         if address.endswith('@ubuntu.com'):
             return address
         if address.endswith('@canonical.com'):
             canonical = address
-        if first is None:
+        if not first:
             first = address
     return canonical or first
 
@@ -148,7 +148,7 @@ class EmailPolicy(BasePolicy, Rest):
         # which is expected to happen when bileto runs britney.
         except IndexError:
             self.log('Email getPublishedSources IndexError (%s %s)' % (pkg, version))
-            return None
+            return []
         return self.scrape_gpg_emails(person_chooser(source))
 
     def apply_policy_impl(self, email_info, suite, source_name, source_data_tdist, source_data_srcdist, excuse):