Rev 29427 added packet_add_new_data_source() with a comment indicating that

Rev 29427 added packet_add_new_data_source() with a comment indicating that
the data source does not need to be allocated if (!tree).

Rev 30158 took the if (!tree) check out indicating that the check was invalid.

So: (since packet_add_new_data_source() now only calls add_new_data_source()),
remove packet_add_new_data_source().

git-svn-id: http://anonsvn.wireshark.org/wireshark/trunk@34717 f5534014-38df-0310-8fa8-9805f1628bb7