[DF] Do not implicitly assume that FillParHelper fills only TH1 and daughters
[DF] Do not implicitly assume that FillParHelper fills only TH1 and daughters

avoiding to call on the objects to fill the `SetDirectory` method.
This change still allows to invoke the aforementioned method in TH1s but
not to perform such operation on instances of other classes.

karies/root,olifre/root,karies/root,root-mirror/root,olifre/root,karies/root,olifre/root,karies/root,olifre/root,karies/root,root-mirror/root,olifre/root,root-mirror/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,karies/root,karies/root,olifre/root,root-mirror/root,olifre/root,root-mirror/root,karies/root,karies/root,olifre/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,karies/root,olifre/root,root-mirror/root