Fixed bug in spaceLink view type
Fixed bug in spaceLink view type

If the external parameter is used and a tiddler belongs to a space
an external link is not created thus tiddler and tiddlyspace attributes
are not set.

This was resulting in an attempt to open an undefined tiddler in bag
undefined. This wraps this special case addressing 578

TiddlySpace/tiddlyspace,FND/tiddlyspace,TiddlySpace/tiddlyspace,FND/tiddlyspace,TiddlySpace/tiddlyspace,FND/tiddlyspace