when dataset is not in DBS3 there should be a clean error

[belforte]

not a tracleback like: crab: Contacting Data Discovery Services ... crab: Accessing DBS at: https://cmsweb.cern.ch/dbs/prod/global/DBSReader crab: Will do Data Discovery using DBS3 crab: DBS3 lookup took 0.09 sec Traceback (most recent call last): File "/afs/cern.ch/user/b/belforte/WORK/CRABDEVEL/python/crab.py", line 927, in crab.initialize(options) File "/afs/cern.ch/user/b/belforte/WORK/CRABDEVEL/python/crab.py", line 181, in initialize self.initializeActions_(opts) File "/afs/cern.ch/user/b/belforte/WORK/CRABDEVEL/python/crab.py", line 521, in initializeActions ncjobs) File "/afs/cern.ch/work/b/belforte/MY_CRAB2/python/Creator.py", line 26, in init self.createJobTypeObject(ncjobs,skip_blocks,self.isNew) File "/afs/cern.ch/work/b/belforte/MY_CRAB2/python/Creator.py", line 75, in createJobTypeObject self.job_type = klass(self.cfg_params,ncjobs,skip_blocks,isNew) File "/afs/cern.ch/work/b/belforte/MY_CRAB2/python/cms_cmssw.py", line 246, in init blockSites = self.DataDiscoveryAndLocation(cfg_params) File "/afs/cern.ch/work/b/belforte/MY_CRAB2/python/cms_cmssw.py", line 401, in DataDiscoveryAndLocation self.pubdata.fetchDBSInfo() File "/afs/cern.ch/work/b/belforte/MY_CRAB2/python/DataDiscovery.py", line 287, in fetchDBSInfo dataType=api3.listDataTypes(dataset=self.datasetPath)[0]['data_type'] IndexError: list index out of range