Fix renaming kwargs when refactoring from imports

[apmorton]

When converting from imports on a large codebase I encountered many files that failed with errors of the form:

Syntax error in file <foo.py> line <123>: expression cannot contain assignment, perhaps you meant "=="?

This was traced back to erroneously renaming keyword arguments that conflicted with renamed imports, resulting in code that looked something like the following:

Before

from os import path
foo(path=path.join('a', 'b'))

After

import os
foo(os.path=os.path.join('a', 'b'))

[lieryan]

The fix looks reasonable, thanks @apmorton!

@all-contributors add @apmorton for code contribution

[allcontributors]

@lieryan

I've put up a pull request to add @apmorton! 🎉