refactor App.get_last_build() to checkupdates

This function is only used in checkupdates, and removing it from the App
class moves the App class one step closer to being a plain dict, which is a
more Pythonic style.

fdroidserver/checkupdates.py

@@ -110,7 +110,7 @@ def check_tags(app, pattern):
 
     vcs.gotorevision(None)
 
-    last_build = app.get_last_build()
+    last_build = get_last_build_from_app(app)
 
     try_init_submodules(app, last_build, vcs)
 
@@ -252,10 +252,7 @@ def check_repomanifest(app, branch=None):
     elif repotype == 'bzr':
         vcs.gotorevision(None)
 
-    last_build = metadata.Build()
-    if app.get('Builds', []):
-        last_build = app.get('Builds', [])[-1]
-
+    last_build = get_last_build_from_app(app)
     try_init_submodules(app, last_build, vcs)
 
     hpak = None
@@ -364,7 +361,7 @@ def possible_subdirs(app):
     else:
         build_dir = Path('build') / app.id
 
-    last_build = app.get_last_build()
+    last_build = get_last_build_from_app(app)
 
     for d in dirs_with_manifest(build_dir):
         m_paths = common.manifest_paths(d, last_build.gradle)
@@ -399,7 +396,7 @@ def fetch_autoname(app, tag):
     except VCSException:
         return None
 
-    last_build = app.get_last_build()
+    last_build = get_last_build_from_app(app)
 
     logging.debug("...fetch auto name from " + str(build_dir))
     new_name = None
@@ -579,6 +576,13 @@ def checkupdates_app(app):
                 raise FDroidException("Git commit failed")
 
 
+def get_last_build_from_app(app):
+    if app.get('Builds'):
+        return app['Builds'][-1]
+    else:
+        return metadata.Build()
+
+
 def status_update_json(processed, failed):
     """Output a JSON file with metadata about this run."""
     logging.debug(_('Outputting JSON'))

fdroidserver/metadata.py

@@ -174,12 +174,6 @@ class App(dict):
         else:
             raise AttributeError("No such attribute: " + name)
 
-    def get_last_build(self):
-        if len(self.Builds) > 0:
-            return self.Builds[-1]
-        else:
-            return Build()
-
 
 TYPE_STRING = 2
 TYPE_BOOL = 3