[pylint] fix global-variable-not-assigned issues

If there is no write access, there is no need for global.  Remove global
statement if there is no assignment.

global-variable-not-assigned:
  Using global for names but no assignment is done Used when a variable is
  defined through the "global" statement but no assignment to this variable is
  done.

In Pylint 2.11 the global-variable-not-assigned checker now catches global
variables that are never reassigned in a local scope and catches (reassigned)
functions [1][2]

[1] https://pylint.pycqa.org/en/latest/whatsnew/2.11.html
[2] https://github.com/PyCQA/pylint/issues/1375

Signed-off-by: Markus Heiser <markus.heiser@darmarit.de>

searx/engines/command.py

@@ -35,7 +35,7 @@ def init(engine_settings):
     if 'command' not in engine_settings:
         raise ValueError('engine command : missing configuration key: command')
 
-    global command, working_dir, result_template, delimiter, parse_regex, timeout, environment_variables
+    global command, working_dir, delimiter, parse_regex, environment_variables
 
     command = engine_settings['command']
 

searx/engines/demo_offline.py

@@ -56,7 +56,6 @@ def search(query, request_params):
     results.
 
     """
-    global _my_offline_engine  # pylint: disable=global-statement
     ret_val = []
 
     result_list = json.loads(_my_offline_engine)

searx/engines/redis_server.py

@@ -31,8 +31,6 @@ def init(_engine_settings):
     )
 
 def search(query, _params):
-    global _redis_client  # pylint: disable=global-statement
-
     if not exact_match_only:
         return search_keys(query)
 
@@ -55,8 +53,6 @@ def search(query, _params):
     return []
 
 def search_keys(query):
-    global _redis_client  # pylint: disable=global-statement
-
     ret = []
     for key in _redis_client.scan_iter(
             match='*{}*'.format(query)

searx/engines/sqlite.py

@@ -35,7 +35,6 @@ def sqlite_cursor():
     * https://docs.python.org/3/library/sqlite3.html#sqlite3.connect
     * https://www.sqlite.org/uri.html
     """
-    global database  # pylint: disable=global-statement
     uri = 'file:' + database + '?mode=ro'
     with contextlib.closing(sqlite3.connect(uri, uri=True)) as connect:
         connect.row_factory = sqlite3.Row
@@ -44,7 +43,6 @@ def sqlite_cursor():
 
 
 def search(query, params):
-    global query_str, result_template  # pylint: disable=global-statement
     results = []
 
     query_params = {

searx/engines/yggtorrent.py

@@ -37,7 +37,6 @@ cookies = dict()
 
 
 def init(engine_settings=None):
-    global cookies
     # initial cookies
     resp = http_get(url, allow_redirects=False)
     if resp.ok: