MySQL: Remove bad GTID from GTID Set
For those who find this later in life..

This was a catastrophic mistake. There is no way to fix this problem. A RESET MASTER / CHANGE MASTER TO must be performed farm wide. Why is it so catastrophic? Because, in a Multi-Master circular replication, ALL the MySQL servers need to have the RESET MASTER / CHANGE MASTER TO performed. 

In MySQL 5.6, the GTID sets are stored in the master BINLOG files - hence why the RESET MASTER must be done. However, when you do a RESET MASTER the command also resets the servers last used GTID to 0. Now the slaves have GTID's larger than the master server. The slave will skip transactions until the GTID exceeds the slaves GTID_EXECUTED_SET value for the master server. That is why you have to perform RESET MASTER / CHANGE MASTER TO on all the slave servers too.

After performing the RESET MASTER / CHANGE MASTER TO we should only need to dump/restore the databases that were being updated on the affected master server (aka master databases) so that they slaves can be in sync.