Fix prop-types crash (fixes #383)

Author: yannickcr

lib/util/Components.js

@@ -304,7 +304,7 @@ function componentRule(rule, context) {
             break;
           }
         }
-        if (!node) {
+        if (!node || !node.value) {
           return null;
         }
         node = node.value;

tests/lib/rules/prop-types.js

@@ -1795,6 +1795,20 @@ ruleTester.run('prop-types', rule, {
       errors: [
         {message: '\'result.notok\' is missing in props validation'}
       ]
+    }, {
+      code: [
+        'let Greetings = {};',
+        'Greetings.Hello = class extends React.Component {',
+        '  render () {',
+        '    return <div>Hello {this.props.name}</div>;',
+        '  }',
+        '}',
+        'Greetings.Hello.propTypes = {};'
+      ].join('\n'),
+      parserOptions: parserOptions,
+      errors: [{
+        message: '\'name\' is missing in props validation'
+      }]
     }
   ]
 });