Add docs/doxygen to .gitignore. (cherry picked from commit c127a3a87e26c94284f80600c287f75a2d80da0b)
Add docs/doxygen to .gitignore.
(cherry picked from commit c127a3a87e26c94284f80600c287f75a2d80da0b)

commshare/pupnp,BelledonneCommunications/libupnp,BelledonneCommunications/libupnp,mrjimenez/pupnp,BelledonneCommunications/libupnp,commshare/pupnp,mrjimenez/pupnp,mrjimenez/pupnp,BelledonneCommunications/libupnp,mrjimenez/pupnp,commshare/pupnp