mdrun signal description incorrect - Redmine #2324

The mdrun help texts list different behavior for when receiving and TERM or an INT signal. But from the code and testing it seems the behavior is identical. So the help text should likely be updated.

(from redmine: issue id 2324, created on 2017-12-03 by berkhess, closed on 2017-12-10)

• Changesets:
  • Revision 50d50553 by Berk Hess on 2017-12-04T08:51:23Z:

Update mdrun signal help text

Updated mdrun help text on signal handling for old and recent changes
to the behavior.

Fixes #2324

Change-Id: I48dd30b7da3a1dc57331978c7d3b0e1509850187