osd: fix osd_reqid_t comparison strict weak ordering

osd: fix osd_reqid_t comparison strict weak ordering

The 'l.inc < r.inc' term in operator< lacked an 'l.name == r.name' guard,
breaking antisymmetry, so it was not a valid strict weak ordering.
Replace it with std::tie.

The only ordered container keyed on osd_reqid_t is
ECInject::write_failures0_reqid (QA/debug error injection), so no
production code path is affected and no backport is needed.

Signed-off-by: Sun Yuechi <sunyuechi@iscas.ac.cn>