Fix potential leak in TLeaf::GenerateOffsetArrayBase
Fix potential leak in TLeaf::GenerateOffsetArrayBase

Appears in error cases when nullptr is returned, 
but allocated memory not released
olifre/root,olifre/root,karies/root,root-mirror/root,root-mirror/root,olifre/root,root-mirror/root,karies/root,karies/root,karies/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,root-mirror/root,root-mirror/root,olifre/root,karies/root,olifre/root,root-mirror/root,karies/root,olifre/root,olifre/root,olifre/root,olifre/root,karies/root,root-mirror/root,karies/root,olifre/root,root-mirror/root,karies/root,root-mirror/root,karies/root