Fixes to make adding multiplex events more robust. If adding events fail mpx_insert_events, the changes made are undone properly. Previously, a failing mpx_insert_events could result in incorrect usage counts and minor memory leakage.
Fixes to make adding multiplex events more robust. If adding events
fail mpx_insert_events, the changes made are undone properly. Previously,
a failing mpx_insert_events could result in incorrect usage counts and
minor memory leakage.

pyrovski/papi,arm-hpc/papi,pyrovski/papi,pyrovski/papi,pyrovski/papi,pyrovski/papi,arm-hpc/papi,pyrovski/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,arm-hpc/papi,pyrovski/papi,arm-hpc/papi,pyrovski/papi