[c++] Catch exception by ref in attribute example (#1067)
[c++] Catch exception by ref in attribute example (#1067)

Resolves a warning emitted by G++ 9.3.0
chwarr/bond,Microsoft/bond,chwarr/bond,Microsoft/bond,chwarr/bond,chwarr/bond,Microsoft/bond,chwarr/bond,chwarr/bond,Microsoft/bond,Microsoft/bond,Microsoft/bond