When re-raising exceptions, use save_and_reraise

In some cases the exception context can be cleared,
resulting in None being attempted to be re-raised after
an exception handler is run.

Change-Id: I16811ba8f0bfaa15199a648748bbc7d7a6a500bc
Partial-Bug:#1281453
Merge "When re-raising exceptions, use save_and_reraise"