crimson/osd: allow ops with non-empty hobject key

crimson/osd: allow ops with non-empty hobject key

Crimson was rejecting OSD ops when hobject_t::key (locator) was non-empty,
returning -ENOTSUP (95). This broke RGW PutObject because RGW uses locators
for object names like "bucket/obj" to ensure objects land in the same PG.

The original code comment claimed locators were only used for multipart
upload clone_range, which is no longer supported. However, RGW still uses
locators for the fundamental object naming scheme, so this check was
incorrectly blocking basic RGW operations.

This fixes s3tests PutObject failing with HTTP 500 / internal error -95
Signed-off-by: Kautilya Tripathi <kautilya.tripathi@ibm.com>