evolve: handle case when newnode can be None while continuing evolve
There can be case when `hg evolve --continue` is run, when working directory is
clean and there is nothing to be included in the new commit. Let's make sure we
handle such cases correctly and obsolete the node which is evolved with parent
of wdir as successor. This is same as what rebase does.
[flake8]
ignore =
#closing bracket does not match indentation of opening bracket's line
E123,
# closing bracket does not match visual indentation
E124,
# visually indented line with same indent as next logical line
E129,
# at least two spaces before inline comment
E261,
# too many leading '#' for block comment
E266,
# expected 2 blank lines, found 0
E302,
# expected 2 blank lines after end of function or class
E305,
# module level import not at top of file
E402,
# line too long (82 > 79 characters)
E501,
# do not assign a lambda expression, use a def
E731,
# class names should use CapWords convention
N801,
# line break occurred before a binary operator
W503
builtins=xrange, execfile