There are some fatal make errors that occur from the current ptest
for lttng-tools however since other tests are successful, those make
build failures were being ignored.
When upgrading, the order of test execution changed and the ptest failed
fatally straight away with the same errors.
Passing -k to make means it will try and run all the tests making the
test suite run more consistently over all lttng-tools versions.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
