[1.7.x] Fixed #23946 -- Fixed runserver crash when socket error contains Unicode chars.

Backport of bba545345f from master

django/core/management/commands/runserver.py

@@ -13,7 +13,7 @@ from django.core.servers.basehttp import run, get_internal_wsgi_application
 from django.db import connections, DEFAULT_DB_ALIAS
 from django.db.migrations.executor import MigrationExecutor
 from django.utils import autoreload
-from django.utils.encoding import get_system_encoding
+from django.utils.encoding import get_system_encoding, smart_text
 from django.utils import six
 from django.core.exceptions import ImproperlyConfigured
 
@@ -142,7 +142,7 @@ class Command(BaseCommand):
             try:
                 error_text = ERRORS[e.errno]
             except KeyError:
-                error_text = str(e)
+                error_text = smart_text(e)
             self.stderr.write("Error: %s" % error_text)
             # Need to use an OS exit because sys.exit doesn't work in a thread
             os._exit(1)

docs/releases/1.7.2.txt

@@ -98,3 +98,6 @@ Bugfixes
 * Fixed a regression in ``contrib.admin`` add/change views which caused some
   ``ModelAdmin`` methods to receive the incorrect ``obj`` value
   (:ticket:`23934`).
+
+* Fixed ``runserver`` crash when socket error message contained Unicode
+  characters (:ticket:`23946`).