Break out of the loop asap.

svn path=/main/trunk/; revision=3474
diff --git a/pym/portage.py b/pym/portage.py
index 787b9d2..d520188 100644
--- a/pym/portage.py
+++ b/pym/portage.py
@@ -3056,6 +3056,7 @@
 						overlays[i], noiselevel=-1)
 				except KeyError:
 					pass
+				break
 
 	return retval