Fix telnet warnings in tests

Disable telnet console if it's not available, else we'll get an extra
warning about failure to enable it, and tests will fail.

tests/test_crawler.py

 import logging
-import os
 import tempfile
 import warnings
 import unittest
@@ -14,8 +13,9 @@ from scrapy.spiderloader import SpiderLoader
 from scrapy.utils.log import configure_logging, get_scrapy_root_handler
 from scrapy.utils.spider import DefaultSpider
 from scrapy.utils.misc import load_object
-from scrapy.utils.test import get_crawler
 from scrapy.extensions.throttle import AutoThrottle
+from scrapy.extensions import telnet
+
 
 class BaseCrawlerTest(unittest.TestCase):
 
@@ -100,6 +100,8 @@ class CrawlerLoggingTestCase(unittest.TestCase):
                 custom_settings = {
                     'LOG_LEVEL': 'INFO',
                     'LOG_FILE': log_file.name,
+                    # disable telnet if not available to avoid an extra warning
+                    'TELNETCONSOLE_ENABLED': telnet.TWISTED_CONCH_AVAILABLE,
                 }
 
             configure_logging()

tests/test_utils_log.py

@@ -10,6 +10,7 @@ from twisted.python.failure import Failure
 from scrapy.utils.log import (failure_to_exc_info, TopLevelFormatter,
                               LogCounterHandler, StreamLogger)
 from scrapy.utils.test import get_crawler
+from scrapy.extensions import telnet
 
 
 class FailureToExcInfoTest(unittest.TestCase):
@@ -65,10 +66,14 @@ class TopLevelFormatterTest(unittest.TestCase):
 class LogCounterHandlerTest(unittest.TestCase):
 
     def setUp(self):
+        settings = {'LOG_LEVEL': 'WARNING'}
+        if not telnet.TWISTED_CONCH_AVAILABLE:
+            # disable it to avoid the extra warning
+            settings['TELNETCONSOLE_ENABLED'] = False
         self.logger = logging.getLogger('test')
         self.logger.setLevel(logging.NOTSET)
         self.logger.propagate = False
-        self.crawler = get_crawler(settings_dict={'LOG_LEVEL': 'WARNING'})
+        self.crawler = get_crawler(settings_dict=settings)
         self.handler = LogCounterHandler(self.crawler)
         self.logger.addHandler(self.handler)