fix some pyflakes errors

pywikibot/site.py:774: local variable 'uidata' is assigned to but never used
pywikibot/site.py:955: local variable 'v' is assigned to but never used
scripts/unlink.py:37: 'config' imported but unused

Change-Id: I883a931248ab0ed52f99a0dad4e191e4b266a016
Merge "fix some pyflakes errors"