Bug 772771

This needs to be validated further but it seems that the agent may
not be picking up updated plugin config at startup.

0) Import RHQ Server resource
1) Shut down agent
2) Enable the built in log event source (and optionally make other changes
   to it)
3) Save new config

This will generate a config update failure because the live config
could not be updated.  But the config is updated in the db and the
config history shows the change, with the agent update error. This,
although maybe not totally intuitive, is expected.

4) Start the agent 

You can do this in debug if you like, and set a break in
public void startLogFileEventPollers().  At the break you should see
that the logEventSource is still disabled and no other changes are
reflected.

No log message events will be generated.

There may be easier ways to repro this, perhaps just changing the 
JNP url and if the resource still connects you know it's not using
the updated value.

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Additionally, given the break point set above, I noticed the component
start() method getting called more than once (without intervening stop()
calls.  This is something to also look into, and will merit another BZ if
it is in fact happening.