[G12] a1c skims correction

[Johann Goetz]

the second to last line here is now correct. it should read "not 2
charged tracks ..."

=== complete set skims (no redundancy) ===
* 1 charged kaon & 1 charged track <inclusive>
** (skims/1ckaon1ctrk)
* 2 positive tracks & 1 negative track, not 1ckaon1ctrk
** (skims/2pos1neg_not_1ckaon1ctrk)
* 2 charged tracks, not 2pos1neg or 1ckaon1ctrk events
** (skims/2ctrk_not_2pos1neg_1ckaon1ctrk)
* not 2 charged tracks or 2pos1neg or 1ckaon1ctrk events
** (skims/not_2ctrk_2pos1neg_1ckaon1ctrk)