TRQ-2828 momctl -q clearmsg doesn't seem to clear error messages permenantly

Fixed a problem in check_state where the local static message
variable would over-write the global message variable for
node health checks in between node check intervals.

Conflicts:

	src/resmom/linux/mom_mach.c
	src/resmom/mom_main.c
	src/resmom/mom_server.c

Conflicts:

	src/resmom/test/mom_server/scaffolding.c
	src/resmom/test/mom_server/test_mom_server.c