readelf: check elf_getarhdr returns NULL in dump_archive_index

Report of the static analyzer:
DEREF_OF_NULL.RET Pointer, returned from function 'elf_getarhdr' at
readelf.c:13551, may be NULL and is dereferenced at readelf.c:13553.

    * src/readelf.c (dump_archive_index): Check elf_getarhdr doesn't
    return NULL.

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov@gmail.com>
1 file changed