kbx: Use wrapper functions for es_fclose and es_fopen.
* kbx/keybox-defs.h (KEYBOX_LL_OPEN_READ) (KEYBOX_LL_OPEN_UPDATE, KEYBOX_LL_OPEN_CREATE): New. * kbx/keybox-init.c (_keybox_ll_open): New. Replace all keybox use of es_fopen by this function. (_keybox_ll_close): New. Replace all keybox use of es_fclose by this function.
Note that this has not been done for the utilities and the backend-kbx
of keyboxd.