[IMPR] Increase skip counter and other improvements
[IMPR] Increase skip counter and other improvements

- increase _skip_counter if page is skipped by SkipPageError exception
- shorten info dict assignments
- shorten initialized_page assignment

Change-Id: I967fe7033a2ad0ee571795adc4984a70d1bc87fc

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