Add extra debug information.
Fix memory leak.
exit failure because this error is unrecoverable
add keep_claim_idle support

Rationale documented in the HTCondor manual: http://research.cs.wisc.edu/htcondor/manual/v8.0/condor_submit.html#79915

Fixes #613.
Merge remote-tracking branch 'ccl/pull/631/head'

* ccl/pull/631/head:
  add keep_claim_idle support
  exit failure because this error is unrecoverable
  Fix memory leak.
  Add extra debug information.