utils: formatting + PEP8 + PEP257

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
utils: fix dateutils.datetime.combine method.

* Adds the missing time.second into the constructor.

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
utils: test convert_datetext_to_datestruct

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>
utils: test date.convert_datestruct_to_dategui

Signed-off-by: Yoan Blanc <yoan.blanc@cern.ch>