[bugfix] Make transferbot.py use source interwiki in edit summary
[bugfix] Make transferbot.py use source interwiki in edit summary

Bug: T185603
Change-Id: I713eeb7cbd528faae2aa5ccb0bc5e98b7b4dea87

magul/pywikibot-core,magul/pywikibot-core,PersianWikipedia/pywikibot-core,wikimedia/pywikibot-core,wikimedia/pywikibot-core