gcc9: fix warnings in TLatex::TLatexFormSize class
gcc9: fix warnings in TLatex::TLatexFormSize class

Default methods should be ok
olifre/root,olifre/root,karies/root,karies/root,root-mirror/root,karies/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,karies/root,karies/root,olifre/root,root-mirror/root,olifre/root,root-mirror/root,olifre/root,olifre/root,karies/root,olifre/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,karies/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,olifre/root,root-mirror/root,root-mirror/root,karies/root