folder: properly factorize initialization and dropping of self.message

Signed-off-by: Nicolas Sebrecht <nicolas.s-dev@laposte.net>

offlineimap/folder/LocalStatusSQLite.py

@@ -48,7 +48,6 @@ class LocalStatusSQLiteFolder(BaseFolder):
         super(LocalStatusSQLiteFolder, self).__init__(name, repository)
         self.root = repository.root
         self.filename = os.path.join(self.getroot(), self.getfolderbasename())
-        self.messagelist = {}
 
         self._newfolder = False        # Flag if the folder is new.
 
@@ -197,7 +196,7 @@ class LocalStatusSQLiteFolder(BaseFolder):
 
     # Interface from BaseFolder
     def cachemessagelist(self):
-        self.messagelist = {}
+        self.dropmessagelistcache()
         cursor = self.connection.execute('SELECT id,flags,mtime,labels from status')
         for row in cursor:
             uid = row[0]
@@ -222,9 +221,6 @@ class LocalStatusSQLiteFolder(BaseFolder):
             self.messagelist[uid]['labels'] = labels
             self.messagelist[uid]['mtime'] = row[2]
 
-    def dropmessagelistcache(self):
-        self.messagelist = {}
-
     # Interface from LocalStatusFolder
     def save(self):
         pass
@@ -282,11 +278,6 @@ class LocalStatusSQLiteFolder(BaseFolder):
     #        assert False,"getmessageflags() called on non-existing message"
 
 
-    # Interface from BaseFolder
-    def getmessagelist(self):
-        return self.messagelist
-
-
     # Interface from BaseFolder
     def savemessage(self, uid, content, flags, rtime, mtime=0, labels=set()):
         """Writes a new message, with the specified uid.