Fix stream_client() in bootstrap.py.

BUG=626380

Review-Url: https://codereview.chromium.org/2131463003
NOKEYCHECK=True
GitOrigin-RevId: 6b78e815ed02585b6701aba195c6506c929eeecf
diff --git a/bootstrap.py b/bootstrap.py
index f5aec6b..3344e5d 100644
--- a/bootstrap.py
+++ b/bootstrap.py
@@ -69,4 +69,4 @@
     """
     if not self.streamserver_uri:
       raise ValueError('No streamserver in bootstrap environment.')
-    return stream.StreamClient.create(self.streamserver_uri)
+    return stream.create(self.streamserver_uri)