Fix: zchunkopen: resources leaks, don't close supplied fd

Fix: zchunkopen: resources leaks, don't close supplied fd

System variant:
- resource leaks when `zck_init_read` or `zck_init_write` fails
- supplied fd will be closed if `zck_create` fails

Libsolv limited zchunk implementation:
- resource leak when `strcmp(mode, "r") != 0`
- supplied fd will be closed if `solv_zchunk_open` fails (Fix is thread
  unsafe. However the original version caused a double-close in the caller
  function and was thread unsafe too.)