E302 False-positive for variable names starting with `def`

Given the following code:

```
defaults = {}
defaults.update()
```

A false positive is reported: `E302 expected 2 blank lines, found 0`.

Changing of the variable name to something that doesn't start with `def` avoids the false positive. This is only triggered in 2.3.0, not 2.2.0.
