even more defensive path expansion (see also 8d381fdef898);

--- a/src/Pure/PIDE/document.scala	Tue Aug 14 11:43:08 2012 +0200
+++ b/src/Pure/PIDE/document.scala	Tue Aug 14 12:21:32 2012 +0200
@@ -51,8 +51,9 @@
     object Name
     {
       val empty = Name("", "", "")
-      def apply(path: Path): Name =
+      def apply(raw_path: Path): Name =
       {
+        val path = raw_path.expand
         val node = path.implode
         val dir = path.dir.implode
         val theory = Thy_Header.thy_name(node) getOrElse error("Bad theory file name: " + path)