oeqa/selftest: Use extraresults on self instead of self.tc
In order to take advantage of multiprocess execution of tests the
extraresults must be passed through the TestResult. With changes to how
oeqa/core handles test cases the extraresults attribute of the testcase
is passed to the TestResult, with passing across process boundaries
handled automatically.
Signed-off-by: Nathan Rossi <nathan@nathanrossi.com> Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
