While reviewing http://review.gluster.com/#change,3565 I noticed that we have nearly a hundred uses of dict_set_dynstr, and a majority of those use gf_strdup'ed values.  This requires callers to check two return values, from gf_strdup and dict_set_dynstr, complicating error recovery.  I'd like to add a dict_set_transient_str function that does the gf_strdup internally, simplifying callers which then only need to check one return value.