Improve comments for shell_path

lib/support/init.d/gitlab.default.example

@@ -30,8 +30,7 @@ web_server_pid_path="$pid_path/unicorn.pid"
 # The default is "$pid_path/sidekiq.pid"
 sidekiq_pid_path="$pid_path/sidekiq.pid"
 
-# shell_path defines the path of shell for "$app_user" in case you disabled
-# shell of "$app_user" by commands like `usermod -s /sbin/nologin $app_user"
-# for security decision.
+# shell_path defines the path of shell for "$app_user" in case you are using
+# shell other than "bash"
 # The default is "/bin/bash"
 shell_path="/bin/bash"