Add a new lttng file to one of the tests to avoid test failures.
Also add a dependency on grep since standalone testing revealed test
failures without this. Normally this was added by other dependencies
in the ptest images so we didn't see this.
(From OE-Core rev: 5799a807eed44d380e142913e50308589b9412ed)
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>