[fix] utils/searxng.sh uses searx.shared module which no longer exists

Issue exists since #1954 has been merged / the PR fixed all searx.shared except
this one fixed here in this commit.

Related: https://github.com/searxng/searxng/pull/1954
Closes: https://github.com/searxng/searxng/issues/3224

utils/searxng.sh

@@ -696,7 +696,7 @@ To install uWSGI use::
         die 42 "SearXNG's uWSGI app not available"
     fi
 
-    if ! searxng.instance.exec python -c "from searx.shared import redisdb; redisdb.initialize() or exit(42)"; then
+    if ! searxng.instance.exec python -c "from searx import redisdb; redisdb.initialize() or exit(42)"; then
         rst_para "\
 The configured redis DB is not available: If your server is public to the
 internet, you should setup a bot protection to block excessively bot queries.