Fix auto-summary in delete.py

mysite was not defined. pywikibot.handleArgs is guaranteed to return
a list (as opposed to a generator) after parsing all global arguments
(such as -lang and -family). This means it's safe to call
pywikibot.getSite immediately after handleArgs, but before handling
local arguments.

Change-Id: I0bd76806e460fec200973a712370e459c9189ea7
Fixes-Change-Id: I386328c62b1bbeb7022a620f8e95d25a67686371