Identified by OS-TIF audit.

TOB-MOSQ-CR-5

- Broker will log warnings if sensitive files are world readable/writable, or
  if the owner/group is not the same as the user/group the broker is running
  as. In future versions the broker will refuse to open these files.

Fix engine keyfile support.

Closes #2799. Thanks to n00b42

Do not add outgoing bridge connection context to session expiry list

Fix sub_count is not decreased when client ubsubscribe

Signed-off-by: NNorbert Heusser <norbert.heusser@cedalo.com>

Signed-off-by: Nlinkkzz <jk588592@163.com>

Do not try to open keyfile when keyform is "engine": this is not necessarily a real file.
Dynamic engines require init with OPENSSL_INIT_ENGINE_DYNAMIC before they can be loaded.
Signed-off-by: NBart Desplanques <bart.desplanques@gmail.com>

Closes #2794. Thanks to Evgeny S.

This occurred with non-matching cleansession/local_cleansession being
expired on start after restoring from persistence.

Closes #2634. Thanks to everyone on the issue.

Closes #2732. Thanks to zhousongsong.

Closes #2673. Thanks to Karl Palsson.

Closes #2692. Thanks to Matt Turner.

Closes #2354.
Closes #2749.

Closes #2746. Thanks to Akos Vandra-Meyer.

Fix malloc size for file path

Closes #2722. Thanks to KramNamez.

fixed a bug where broker's private-key file was not loaded

Signed-off-by: NTobias Assarsson <tobias.assarsson@gmail.com>

fixed a bug where the mosquitto-broker's private-key file(.pem)
dose not load with tls-engine.
Signed-off-by: NHyeongon Kim <khyeongon@gmail.com>