Description of problem:
Today retrace server just checks the mtime of the task directory and removes the task if it is too old (a failed task is removed with different timeframe than a success task).  We need another check to make sure the vmcore (crash/vmcore) is not open before removal.  Any instance of this occurring may be a case where people have forgotten to close their crash session, but could also be due to a 'failed task' but somehow the vmcore is usable.  The latter is a real possibility, and we have at least one open bug about it today -  https://bugzilla.redhat.com/show_bug.cgi?id=1149356).  In any case, retrace should not remove tasks if it's associated with an open vmcore.

Version-Release number of selected component (if applicable):
retrace-server-1.12-3.el6.noarch

How reproducible:
Easily reproducible but in practice on our system I've only seen it a couple times (likely due to our DeleteFailedTaskAfter or DeleteTaskAfter settings), and I can't recall anyone complaining recently though some have brought it up.

Steps to Reproduce:
1. Run 'retrace-server-worker <task> crash' on a vmcore and leave it open for longer than the delete rules (either DeleteFailedTaskAfter or DeleteTaskAfter)

Actual results:
task is removed even though someone has the 'crash/vmcore' file open

Expected results:
task is not removed if someone has the 'crash/vmcore' file open

Additional info:
Documented, but low priority for us due to fairly large value of DeleteTaskAfter (we have 6 mo right now), and low incidence.  If we ever lower the values of DeleteFailedTaskAfter or DeleteTaskAfter, or there's a higher rate of 'failed tasks' which are still useful, it may become more of an issue.