Description of problem:
When the CommandDelegate creates a new session it first tries to load it to make sure it hasn't been created yet. In that case an exception is thrown, which signals the session does not exist and can be created, which is expected. However the exception is always logged at ERROR level. The log should not be polluted with error messages that don't signal a real problem.

Version-Release number of selected component (if applicable):
ER2 - jBPM 5.2.1-snapshot

How reproducible:
always

Steps to Reproduce:
1. after booting the server, open Process Overview
2. check server log
  
Actual results:
an error is always logged when accessing the Process Overview, although nothing unexpected actually happens

Expected results:
error should be logged only if an unexpected exception is encountered

Additional info:
see attached server log