OCFileListFragment: set title when attached to activity

This prevents wrong title while search isn't started yet (such as when returning to a search fragment from a preview fragment)

Signed-off-by: Álvaro Brey Vilas <alvaro.brey@nextcloud.com>

src/main/java/com/owncloud/android/ui/fragment/OCFileListFragment.java

@@ -259,6 +259,7 @@ public class OCFileListFragment extends ExtendedListFragment implements
         Log_OC.i(TAG, "onAttach");
         try {
             mContainerActivity = (FileFragment.ContainerActivity) context;
+            setTitle();
 
         } catch (ClassCastException e) {
             throw new IllegalArgumentException(context.toString() + " must implement " +