tmf: Add missing schema in build.properties

tmf: Add missing schema in build.properties

Otherwise, adding the extension without full source code throws an
exception because of the missing schema.

Change-Id: I325f0ca070d73c87b1a789c7691a9bd244cf51c3
Signed-off-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Reviewed-on: https://git.eclipse.org/r/85240
Reviewed-by: Hudson CI
Reviewed-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Tested-by: Matthew Khouzam <matthew.khouzam@ericsson.com>
Reviewed-by: Jean-Christian Kouame <jean-christian.kouame@ericsson.com>
Tested-by: Jean-Christian Kouame <jean-christian.kouame@ericsson.com>