oeqa/core/runner: Don't log details twice if test fails
The details of a test failure is upper on the unittest output
so don't log twice the actual failure.
[YOCTO #11622]
(From OE-Core rev: 0f2e81c2a4458ad0ec6bab2710952ac2c2bbf1af)
Signed-off-by: Aníbal Limón <anibal.limon@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>