More verbose loggin

Thread names are used to determine the logging header in the TTY ui. A
recent change made them too terse (basically only changing the account
name and not the folder names). Unbreak.

Signed-off-by: Sebastian Spaeth <Sebastian@SSpaeth.de>

Changelog.draft.rst

@@ -16,6 +16,8 @@ New Features
 Changes
 -------
 
+* Indicate progress when copying many messages (slightly change log format)
+
 Bug Fixes
 ---------
 

offlineimap/accounts.py

@@ -281,7 +281,7 @@ class SyncableAccount(Account):
                 thread = InstanceLimitedThread(\
                     instancename = 'FOLDER_' + self.remoterepos.getname(),
                     target = syncfolder,
-                    name = "Folder sync [%s]" % self,
+                    name = "Folder %s [acc: %s]" % (remotefolder, self),
                     args = (self.name, remoterepos, remotefolder, localrepos,
                             statusrepos, quick))
                 thread.setDaemon(1)