Add functools.wraps decorator to rbac_rule_validation

This adds functools.wraps [0] to rbac_rule_validation decorator.
"This takes a function used in a decorator and adds the functionality
of copying over the function name, docstring, arguments list, etc." which
is quite convenient [1].

Also stops adding the role as a testcase attribute which can cause
filtering issues via regular expressions when the role doesn't match
the role in tempest.conf under ``[patrole].rbac_test_role``.

[0] https://docs.python.org/2/library/functools.html#functools.wraps
[1] https://stackoverflow.com/questions/308999/what-does-functools-wraps-do

Change-Id: I8fde00e4f9332ba9b9ea94edc714d87ab9e1b851
1 file changed