Klever

The following exception occurs if error trace to be processed is empty:

Raise exception:
Traceback (most recent call last):
  File "/home/ubuntu/klever/core/core/components.py", line 116, in run
    self.main()
  File "/home/ubuntu/klever/core/core/utils.py", line 56, in callbacks_caller
    ret = attr(*args, **kwargs)
  File "/home/ubuntu/klever/core/core/vtg/rsb.py", line 46, in generate_verification_tasks
    self.decide_verification_task()
  File "/home/ubuntu/klever/core/core/utils.py", line 56, in callbacks_caller
    ret = attr(*args, **kwargs)
  File "/home/ubuntu/klever/core/core/vtg/rsb.py", line 322, in decide_verification_task
    raise self.witness_processing_exception
  File "/home/ubuntu/klever/core/core/vtg/rsb.py", line 426, in process_single_verdict
    et = import_error_trace(self.logger, witnesses[0])
  File "/home/ubuntu/klever/core/core/vtg/et/__init__.py", line 25, in import_error_trace
    po = ErrorTraceParser(logger, witness)
  File "/home/ubuntu/klever/core/core/vtg/et/parser.py", line 31, in __init__
    self._parse_witness(witness)
  File "/home/ubuntu/klever/core/core/vtg/et/parser.py", line 48, in _parse_witness
    sink_nodes_map = self.__parse_witness_nodes(graph)
  File "/home/ubuntu/klever/core/core/vtg/et/parser.py", line 84, in __parse_witness_nodes
    if not self.error_trace.entry_node:
  File "/home/ubuntu/klever/core/core/vtg/et/error_trace.py", line 56, in entry_node
    return self._nodes[self._entry_node_id]
KeyError: 'A236192'

How to reproduce:
Linux kernel: 4.2.6
Klever version: master (d70964d).
CPAchecker version: ldv-bam:24643
Rule: linux:usb:dev
Module: drivers/net/wireless/at76c50x-usb.ko, drivers/mmc/host/vub300.