utils: Use hostname for netrc instead split netloc

This patch uses the "hostname" attribute from the parsed url to get the
host, instead of trying to calculate the host from netloc that can
produce errors when "http://username:password@domain.com" format is
used.

Author: danigm

src/requests/utils.py

@@ -236,13 +236,7 @@ def get_netrc_auth(url, raise_errors=False):
             return
 
         ri = urlparse(url)
-
-        # Strip port numbers from netloc. This weird `if...encode`` dance is
-        # used for Python 3.2, which doesn't support unicode literals.
-        splitstr = b":"
-        if isinstance(url, str):
-            splitstr = splitstr.decode("ascii")
-        host = ri.netloc.split(splitstr)[0]
+        host = ri.hostname
 
         try:
             _netrc = netrc(netrc_path).authenticators(host)