tests: add ERP5_scalability class
scalability: runScalabilityTestSuite: use suite class to get suite informations
scalability: runScalabilityTestSuite: do not cleanup tester log files
testnode: SlapOSMasterCommunicator: repeat curl one more time if it fails
tests: fix test name into ERP5_scalability
scalability: runScalabilityTestSuite: Correct bugs
testnode: ScalabilityTestRunner: Destroy instance correctly