Add timeout to use of curl in bootstrap.py.

Author: kennytm

src/bootstrap/bootstrap.py

@@ -88,7 +88,10 @@ def _download(path, url, probably_big, verbose, exception):
             option = "-#"
         else:
             option = "-s"
-        run(["curl", option, "--retry", "3", "-Sf", "-o", path, url],
+        run(["curl", option,
+             "-y", "30", "-Y", "10",    # timeout if speed is < 10 bytes/sec for > 30 seconds
+             "--connect-timeout", "30", # timeout if cannot connect within 30 seconds
+             "--retry", "3", "-Sf", "-o", path, url],
             verbose=verbose,
             exception=exception)