ctf: Lock the CTF test-suite to an older known commit

New test cases have been added to the upstream CTF test suite.
More work would have to be done to support them, so for now keep
the older version of the testsuite.

Change-Id: I06533373a287494e8334e2c07264c83889dd5568
Signed-off-by: Alexandre Montplaisir <alexmonthy@voxpopuli.im>
Reviewed-on: https://git.eclipse.org/r/36587
Tested-by: Hudson CI
Reviewed-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>
Tested-by: Marc-Andre Laperle <marc-andre.laperle@ericsson.com>