This closes#2062 by clarifying in the docs which auth
header takes precedence:
1st auth=
2nd .netrc
3rd headers=
This precedence order is already tested in test_requests.py,
in the test_basicauth_with_netrc method. Perhaps we should
add further tests for non-basic auth schemes.
The documentation does not make it clear that when the credentials
from netrc are used, Requests authenticates with HTTP Basic Auth.
I just spent ages trying to figure out why it wasn't working, and
it was because although the credentials in the netrc were correct,
the server actually required HTTP Digest Auth.
Add a section in the authentication documentation to make it clear
that HTTP Basic Auth is used.
Isa Hassen