New Project Wizard: Recheck existence of directory after browsing

The user might create directories or delete them while in the browsing
interface, thus in the PathChooser trigger a validation after browsing.

Task-Nr: QTCREATORBUG-3105
Reviewed-By: Friedemann Kleint

src/libs/utils/pathchooser.cpp

@@ -270,6 +270,7 @@ void PathChooser::slotBrowse()
     }
 
     emit browsingFinished();
+    m_d->m_lineEdit->triggerChanged();
 }
 
 bool PathChooser::isValid() const