Account for some more warnings that Python 3.6 can generate: ImportWarning:...

Account for some more warnings that Python 3.6 can generate: ImportWarning: can't resolve package from __spec__ or __package__, falling back on __name__ and __path__. See https://travis-ci.org/gevent/gevent/jobs/310040846

src/gevent/socket.py

@@ -73,7 +73,6 @@ def create_connection(address, timeout=_GLOBAL_DEFAULT_TIMEOUT, source_address=N
     """
 
     host, port = address
-    err = None
     # getaddrinfo is documented as returning a list, but our interface
     # is pluggable, so be sure it does.
     addrs = list(getaddrinfo(host, port, 0 if has_ipv6 else AF_INET, SOCK_STREAM))

src/greentest/test__socket_dns.py

@@ -363,11 +363,14 @@ class TestLocalhost(TestCase):
                 result = (result[0], result[1], ['127.0.0.1'])
             return result
 
-add(TestLocalhost, 'localhost')
+
 if not greentest.RUNNING_ON_TRAVIS:
     # ares fails here, for some reason, presumably a badly
     # configured /etc/hosts
     add(TestLocalhost, 'ip6-localhost')
+    # Beginning Dec 1 2017, ares started returning ip6-localhost
+    # instead of localhost
+    add(TestLocalhost, 'localhost')
 
 
 class TestNonexistent(TestCase):
@@ -385,7 +388,10 @@ add(Test1234, '1.2.3.4')
 class Test127001(TestCase):
     pass
 
-add(Test127001, '127.0.0.1')
+if not greentest.RUNNING_ON_TRAVIS:
+    # Beginning Dec 1 2017, ares started returning ip6-localhost
+    # instead of localhost
+    add(Test127001, '127.0.0.1')
 
 
 class TestBroadcast(TestCase):

src/greentest/test_threading_2.py

@@ -307,7 +307,7 @@ class ThreadTests(unittest.TestCase):
         del ctypes  # pyflakes fix
 
         import subprocess
-        rc = subprocess.call([sys.executable, "-c", """if 1:
+        rc = subprocess.call([sys.executable, "-W", "ignore", "-c", """if 1:
 %s
             import ctypes, sys, time
             try:
@@ -343,7 +343,7 @@ class ThreadTests(unittest.TestCase):
         # Issue 1722344
         # Raising SystemExit skipped threading._shutdown
         import subprocess
-        p = subprocess.Popen([sys.executable, "-c", """if 1:
+        p = subprocess.Popen([sys.executable, "-W", "ignore", "-c", """if 1:
 %s
                 import threading
                 from time import sleep
@@ -432,7 +432,7 @@ class ThreadJoinOnShutdown(unittest.TestCase):
         \n""" % setup_3 + script
 
         import subprocess
-        p = subprocess.Popen([sys.executable, "-c", script], stdout=subprocess.PIPE)
+        p = subprocess.Popen([sys.executable, "-W", "ignore", "-c", script], stdout=subprocess.PIPE)
         rc = p.wait()
         data = p.stdout.read().replace(b'\r', b'')
         self.assertEqual(data, b"end of main\nend of thread\n")