Only mark component types as used, not prop names.

[burnnat]

Previously, all JSX identifiers were marked as "used", even for prop names. This is an issue in cases where component props happened by chance to have the same name as a local variable, like this:

    var App;
    var foo;
    React.render(<App foo="bar"/>);

Here, the "foo" prop prevents the foo variable from being marked as unused and ESLint gives no warnings for the no-unused-vars rule, even though foo is not actually referenced anywhere.

This change updates the jsx-uses-vars rule to only mark variables as used if they occur in a JSXOpeningElement node (thus excluding prop names, as they exist in JSXAttribute nodes instead).

[coveralls]

Coverage remained the same at 93.92% when pulling 3fc121b on burnnat:fix-jsx-props into 3e2e92d on yannickcr:master.

[coveralls]

Coverage remained the same at 93.92% when pulling 3fc121b on burnnat:fix-jsx-props into 3e2e92d on yannickcr:master.

[yannickcr]

Nice catch! Thanks!