oeqa/loader: Fix deprecation warning

Clean up the warning:
meta/lib/oeqa/core/loader.py:27: DeprecationWarning: inspect.getargspec() is deprecated, use inspect.signature() or inspect.getfullargspec()
  _failed_test_args = inspect.getargspec(unittest.loader._make_failed_test).args

(From OE-Core rev: d2deb66830be2d44532fea3d5db763b57778252a)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/lib/oeqa/core/loader.py

@@ -24,7 +24,7 @@ from oeqa.core.decorator import decoratorClasses, OETestDecorator, \
 # Generate the function definition because this differ across python versions
 # Python >= 3.4.4 uses tree parameters instead four but for example Python 3.5.3
 # ueses four parameters so isn't incremental.
-_failed_test_args = inspect.getargspec(unittest.loader._make_failed_test).args
+_failed_test_args = inspect.getfullargspec(unittest.loader._make_failed_test).args
 exec("""def _make_failed_test(%s): raise exception""" % ', '.join(_failed_test_args))
 unittest.loader._make_failed_test = _make_failed_test