osd: do not proxy reads unless all OSDs proxy features too

osd: do not proxy reads unless all OSDs proxy features too

Specifically, the object_copy_data_t encoding changed such that the reply
encoding is dependent on features; if we proxy such a read to an old
OSD it will use *our* features to encode instead of the original OSD's.

This effectively conditionally reverts 8e145e08ede625adfb5d41216d7777d6c9707bd0
when the cluster features aren't all present.

Fixes: #10788
Signed-off-by: Sage Weil <sage@redhat.com>