Improve performance of safe_log().
Improve performance of safe_log().

This patch addresses a minor performance regression in a recent change
to this function.  This change ensures that the deep copy is only done
if we really need to.  Previously, the deep copy was being done for all
messages that included a 'method', not just messages with a method that
contain an argument to be sanitized.

Change-Id: I190c5963ecaf70b0aea4e12a2fdc19deb5c1fea2

n0ano/gantt,n0ano/gantt