tmf: Use getter methods instead of fields in TmfEvent#equals()

tmf: Use getter methods instead of fields in TmfEvent#equals()

Since the various getter methods in TmfEvent are not final,
which means that subclasses can (and do) extend them, the
method calls should be used instead of the object's fields
to correctly compare two such objects.

Refs bug #471733.

Change-Id: I2f4a2b8f455cfecd2b2a11f480092cd751eb50d3
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-on: https://git.eclipse.org/r/51139
Reviewed-by: Hudson CI
Reviewed-by: Patrick Tasse <patrick.tasse@gmail.com>