gpg: Add debug flag "recsel".
* g10/gpg.c: Include recsel.h. (debug_flags): New flag "recsel". (set_debug): Set it. * g10/options.h (DBG_RECSEL_VALUE, DBG_RECSEL): New. * g10/import.c (impex_filter_getval): Add debug diagnostics. * g10/keylist.c (parse_and_set_list_filter): Dump the record filter. * common/recsel.c (recsel_debug): New variable. (recsel_set_debug): New function. (recsel_select): Add debug output if requested.