fix(PatternStopsLayer): fix undefined patternStop

Author: landonreed

lib/editor/components/map/PatternStopsLayer.js

@@ -22,7 +22,7 @@ export default class PatternStopsLayer extends Component {
       setActiveStop,
       stops
     } = this.props
-    const stopNotFound = activePattern && activePattern.patternStops.findIndex(ps => ps.id === activePatternStop.id) === -1
+    const stopNotFound = activePattern && activePatternStop && activePattern.patternStops && activePattern.patternStops.findIndex(ps => ps.id === activePatternStop.id) === -1
     return (
       <FeatureGroup id='PatternStops'>
         {stops && activePattern && editSettings.showStops