Previously, the list of configuration paths for get_config_paths

could have duplicates in the case where the current working directory

is a subdirectory of the home directory and a configuration file exists

in the home directory. This will lead to the config in the home

directory being parsed twice, which is undesirable.
Also the documentation in get_config_paths was incorrect as to the

order of precedence in the returned list of paths. This has been

corrected.

Ran unit tests.
Posted this review request.
Checked the output of get_config_paths before and after applying this

patch. Before applying this patch, my ~/.reviewboardrc appears in the

list of config paths twice. After applying this patch, it only appears

once and is the last element of the list.
Manually verified the result of load_config to ensure that my

./reviewboardrc was only parsed once.