Sanitize passwords when logging payload in wsgi

adminPass (or admin_pass) can be either part of a json object or
an xml element or xml attribute. The patch includes
regexps to support all these cases and adds tests
as well

Change-Id: Ic119f986a03863c1d13b566b4c005f3bc77d83d0
Closes-Bug: 1231263
(cherry picked from commit c6d82083295e9b1b42f22d3a2d25a1ab7d341a13)
Merge "Sanitize passwords when logging payload in wsgi" into stable/havana