Fix zerver.lib.utils.generate_random_token.

generate_random_token used to return a value of type six.binary_type
and its return type was annotated as `str`.  This commit fixes that
by making it return a value of type `six.text_type` and updating
the annotation accordingly.
Also fix clashing annnotations.

zerver/lib/utils.py

@@ -110,5 +110,5 @@ def log_statsd_event(name):
     statsd.incr(event_name)
 
 def generate_random_token(length):
-    # type: (int) -> str
-    return base64.b16encode(os.urandom(length // 2)).lower()
+    # type: (int) -> text_type
+    return base64.b16encode(os.urandom(length // 2)).decode('utf-8').lower()

zerver/models.py

@@ -541,7 +541,7 @@ class MitUser(models.Model):
     status = models.IntegerField(default=0)
 
 def generate_email_token_for_stream():
-    # type: () -> str
+    # type: () -> text_type
     return generate_random_token(32)
 
 class Stream(models.Model):

zerver/views/__init__.py

@@ -961,7 +961,7 @@ def update_pointer_backend(request, user_profile,
     return json_success()
 
 def generate_client_id():
-    # type: () -> str
+    # type: () -> text_type
     return generate_random_token(32)
 
 # The order of creation of the various dictionaries are important.