Fix event bus instance leak

[riccardomodanese]

Signed-off-by: riccardomodanese riccardo.modanese@eurotech.com

Brief description of the PR.
Fix a possible leak on Event Bus.
When the Event Bus tries a re-start and, for some reason, the start throws an exception, the new instance will be not properly cleaned.
Added a clean-up

Related Issue
none

Description of the solution adopted
none

Screenshots
none

Any side note on the changes made
none

[codecov]

Codecov Report

Merging #2924 into develop will increase coverage by 0.15%.
The diff coverage is 26.82%.

@@              Coverage Diff              @@
##             develop    #2924      +/-   ##
=============================================
+ Coverage      56.01%   56.17%   +0.15%     
- Complexity      2525     2535      +10     
=============================================
  Files           1040     1040              
  Lines          22578    22597      +19     
  Branches        2037     2039       +2     
=============================================
+ Hits           12648    12694      +46     
+ Misses          8998     8975      -23     
+ Partials         932      928       -4     

Impacted Files	Coverage Δ	Complexity Δ
.../eclipse/kapua/commons/event/ServiceInspector.java	0.00% <0.00%> (ø)	0.00 <0.00> (ø)
...se/kapua/commons/event/jms/JMSServiceEventBus.java	22.80% <27.50%> (+1.75%)	0.00 <0.00> (ø)
...obDeviceManagementOperationManagerServiceImpl.java	73.17% <0.00%> (-6.10%)	13.00% <0.00%> (-1.00%)
.../jbatch/persistence/JPAPersistenceManagerImpl.java	31.60% <0.00%> (+1.03%)	30.00% <0.00%> (ø%)
...plugin/authentication/UserAuthenticationLogic.java	76.78% <0.00%> (+1.78%)	0.00% <0.00%> (ø%)
...apua/job/engine/jbatch/JobEngineServiceJbatch.java	51.85% <0.00%> (+1.85%)	8.00% <0.00%> (ø%)
...atch/persistence/jpa/JpaExecutionInstanceData.java	90.24% <0.00%> (+2.43%)	23.00% <0.00%> (+1.00%)
...a/org/eclipse/kapua/transport/mqtt/MqttClient.java	62.19% <0.00%> (+6.09%)	14.00% <0.00%> (ø%)
.../DeviceManagementOperationRegistryServiceImpl.java	73.21% <0.00%> (+7.14%)	16.00% <0.00%> (+4.00%)
...ransport/mqtt/pooling/PooledMqttClientFactory.java	71.42% <0.00%> (+9.52%)	7.00% <0.00%> (ø%)
... and 6 more

[stefanomorson]

Moving the listener to its own class is ok but stopping the retries is probably the most important change here. Agree with these two.
I'm a bit concerned that there could be a race condition on the restart() method due to the fact that while the restart is in execution a new exception coming from the old instance or the new instance may trigger a new restart process. However, if restart is going to be synchronized, we have to make sure that the onException() method originating it must not block the qpid library underneath.