Fix introspection code in fetch() so that it works correctly when myuris is
an OrderedDict instance. This fixes broken fetching for some packages.

svn path=/main/trunk/; revision=15019
diff --git a/pym/portage/__init__.py b/pym/portage/__init__.py
index 7ed9df4..c13a714 100644
--- a/pym/portage/__init__.py
+++ b/pym/portage/__init__.py
@@ -4511,7 +4511,8 @@
 		locations = mymirrors
 
 	file_uri_tuples = []
-	if isinstance(myuris, dict):
+	# Check for 'items' attribute since OrderedDict is not a dict.
+	if hasattr(myuris, 'items'):
 		for myfile, uri_set in myuris.items():
 			for myuri in uri_set:
 				file_uri_tuples.append((myfile, myuri))