BLXI-136: investigate whether cvscan need to continuously monitor EpicsDlsMcsSis3820$RealTimeListener
2 code changes as described in this issue
http://jira.diamond.ac.uk/browse/BLXI-136
Merge branch '8.38' of ssh://dascgitolite@dasc-git.diamond.ac.uk/gda/gda-epics.git into 8.38
GDA-5941:  commit 8db546a693dca7c6c1bbecb46234b7002bfbe9be causes mythen data reduction sometime to fail due to wrong exception throw.

move sleep to before state checking again immediately after setting to give time for epics to respond.

related to issue in BLXI-126
http://jira.diamond.ac.uk/browse/GDA-5941