fix for uri creation when host is null

compiler/java/com/google/dart/compiler/PackageLibraryManager.java

Index: compiler/java/com/google/dart/compiler/PackageLibraryManager.java
===================================================================
--- compiler/java/com/google/dart/compiler/PackageLibraryManager.java	(revision 19695)
+++ compiler/java/com/google/dart/compiler/PackageLibraryManager.java	(working copy)
@@ -207,7 +207,12 @@
     shortUri = getRelativeUri(uri);
     if (shortUri != null){
       try {
-        return new URI(null, null, shortUri.getScheme() + ":" +  shortUri.getHost() + shortUri.getPath(),null, null);
+        if (shortUri.getHost() != null){
+          return new URI(null, null, shortUri.getScheme() + ":" +  shortUri.getHost() + shortUri.getPath(),null, null);
+        }
+        else {
+          return new URI(null, null, shortUri.getScheme() + ":" +  shortUri.getSchemeSpecificPart(), null, null);
+        }
       } catch (URISyntaxException e) {
       }
     }