JSX bare attributes throw exception

[remko]

When I run jsxgettext on the following JS(X) snippet:

const x = <input required/>;

I get an exception:

jsxgettext/lib/jsxgettext.js:29
    if (node.value.type === 'JSXExpressionContainer') {
                  ^

TypeError: Cannot read property 'type' of null
    at Object.assign.JSXAttribute (jsxgettext/lib/jsxgettext.js:29:19)
    at c (jsxgettext/node_modules/acorn/dist/walk.js:38:15)

Changing the bare attribute to required={true} fixes the error.

[BYK]

Fixed by #107.