Fix when entry is None.

When the tree is not versionned, svn can return <info></info>.

R=dpranke@chromium.org
BUG=
TEST=

Review URL: http://codereview.chromium.org/6899052

git-svn-id: svn://svn.chromium.org/chrome/trunk/tools/depot_tools@83020 0039d316-1c4b-4281-b951-d872f2087c98

scm.py

@@ -518,6 +518,8 @@ class SVN(object):
     if info is None:
       return result
     entry = info.find('entry')
+    if entry is None:
+      return result
 
     # Use .text when the item is not optional.
     result['Path'] = entry.attrib['path']