resulttool/regression.py: skip checking status for ptestresult.rawlogs/ptestresult...

resulttool/regression.py: skip checking status for ptestresult.rawlogs/ptestresult.sections

ptestresult.rawlogs/ptestresult.sections don't have status is expected,
so skip them to avoid following error when running "resulttool regression
base target":

ERROR: Failed to retrieved base test case status: ptestresult.rawlogs
ERROR: Failed to retrieved base test case status: ptestresult.sections

Signed-off-by: Changqing Li <changqing.li@windriver.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>