Properly wait for NM process to finish
Properly wait for NM process to finish

Otherwise tests running after this one might try to bring up a NM and fail to
do so because the previous process still hasn't freed some ports; in particular
the RPC port is the last one to be freed and was causing problems.

Signed-off-by: Rodrigo Tobar <bd955c861cbec2e41c0959cf13c7f573fa307e58@icrar.org>

steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge,steve-ord/daliuge