Facility name disapears with merging #40
Description
When I merge GW_Ori files (files from LITpro test folder in CVS), the facility name becomes undefined:
% oilist GW_Ori.200*
target_name s_ra s_dec t_exptime t_min t_max em_res_power em_min em_max facility_name instrument_name nb_vis nb_vis2 nb_t3 nb_channels
GW_Ori 82.28334 11.87 0.0 52973.32806712948 52973.38412037026 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 IOTA_AB IONIC3 0 18 6 1
GW_Ori 82.28334 11.87 0.0 52974.37421296304 52974.37674768502 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 IOTA_AB IONIC3 0 9 3 1
GW_Ori 82.28334 11.87 0.0 53351.20174189797 53351.39668981498 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 IOTA_AB IONIC3 0 57 19 1
GW_Ori 82.28334 11.87 0.0 53353.34997685207 53353.38156828703 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 IOTA_AB IONIC3 0 18 6 1
GW_Ori 82.28334 11.87 0.0 53354.35648148134 53354.38167824084 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 IOTA_AB IONIC3 0 12 4 1
GW_Ori 82.28334 11.87 0.0 53355.22764467588 53355.26708333334 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 IOTA_AB IONIC3 0 15 5 1
GW_Ori 82.28334 11.87 0.0 53359.32408564817 53359.35291666677 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 IOTA_AB IONIC3 0 9 3 1
% oimerge -o GW_Ori.2004Dec_merged.oifits GW_Ori.2004Dec.A28B*
Writing: GW_Ori.2004Dec_merged.oifits
% oilist GW_Ori.2004Dec_merged.oifits
target_name s_ra s_dec t_exptime t_min t_max em_res_power em_min em_max facility_name instrument_name nb_vis nb_vis2 nb_t3 nb_channels
GW_Ori 82.28334 11.87 0.0 53351.20174189797 53351.39668981498 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 UNDEFINED IONIC3 0 57 19 1
GW_Ori 82.28334 11.87 0.0 53353.34997685207 53353.38156828703 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 UNDEFINED IONIC3 0 18 6 1
GW_Ori 82.28334 11.87 0.0 53354.35648148134 53354.38167824084 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 UNDEFINED IONIC3 0 12 4 1
GW_Ori 82.28334 11.87 0.0 53355.22764467588 53355.26708333334 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 UNDEFINED IONIC3 0 15 5 1
GW_Ori 82.28334 11.87 0.0 53359.32408564817 53359.35291666677 6.6666665135530785 1.6499999446750735E-6 1.6499999446750735E-6 UNDEFINED IONIC3 0 9 3 1