safe_setup preserve original trace

When safe_setup reraies the exception the traceback was
replaced by the trace of the re-raise postion.

This change is aiming to preserve the original stack trace,
by saving the original trace and raiseing new exception from the same
type with the original trace.

Change-Id: I16851a0c1d40d7f7253c23f066fa8c19267f4d9a
Merge "safe_setup preserve original trace"