tmf: Make TmfEventField's equals() also check the sub-fields

tmf: Make TmfEventField's equals() also check the sub-fields

If two TmfEventField objects have the same name/value but different
sub-fields, they were considered equals. With this patch, they also
need the same sub-fields.

Change-Id: I7e07a5624348b812878e1934425a29fba4737e4c
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-on: https://git.eclipse.org/r/30001
Tested-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>