tests/test-check-pyflakes.t

trydiff: use 'not in addedset' for symmetry with 'not in removedset'

With the previous change in place, we can safely use 'addedset'.

#require test-repo pyflakes

  $ cd "`dirname "$TESTDIR"`"

run pyflakes on all tracked files ending in .py or without a file ending
(skipping binary file random-seed)

  $ hg locate 'set:**.py or grep("^!#.*python")' 2>/dev/null \
  > | xargs pyflakes 2>/dev/null | "$TESTDIR/filterpyflakes.py"
  tests/filterpyflakes.py:58: undefined name 'undefinedname'