cur_ifo_bits is incorrectly used

cur_ifo_bits is initialised in postcoh.c to refer to the enabled ifos that are not currently gap (i.e. 101 for a HV run, 1100 for a VK run (if neither gap)).
It is then used in postcoh_kernel.cu to refer to IFOs in pad order (i.e. 11 for a HV run, 11 for a VK run (if neither gap)).
For non-sequential runs this introduces a bug where checks against cur_ifo_bits are checking against the wrong ifo_id's.