AthAnalysisBaseComps: Fix AthAnalysisHelper::setProperty.

AthAnalysisHelper::setProperty was changed from IJobOptionsSvc::addPropertyToCatalogue to IOptionsSvc::set. However, the functionality is not identical. When settingg a string property, the old interface would strip off quotes surrounding the value; the new interface does not do this. Further, the code in AthAnalysisHelper would uncoditionally use Gaudi::Utils;:toString, which adds quotes around values which are strings.

So if we have something convertible to a string, don't use toString().