Revert "c_read_operations.cc: fix resource leak"

This reverts commit 3cd751b0a280909510c3e633cc8cd4b9f5e3b2d9.

A rados_release_read_op() has already been performed, but coverity
didn't recognize that as releasing memory.

Fixes: #7621

Signed-off-by: David Zafman <david.zafman@inktank.com>
Reviewed-by: Samuel Just <sam.just@inktank.com>