Add a new separate test for add_error_handling

Also, clean it up a little.
Make the tests pass
Don't shadow names (lint)
Fix lint (whitespace)
Clean up
Make the test pass
GetRequestFuncTests: self.request*_func*
BindServiceTests: self.request*_func*
Fix lint, introduce intermediary var
Fix lint, introduce intermediary var
Improve docstring
Fix docstring grammar
Lint: line length
Lint: line length
Uppercase HTTP methods
Lint: line length
Use has_code

This fixes the tests
Merge pull request #834 from rackerlabs/add-error-handling-pred

Change add_error_handling to use a pred rather than status codes