memory: scoped_critical_alloc_section: [[maybe_unused]] if not SEASTAR_ENABLE_ALLOC_FAILURE_INJECTION
memory: scoped_critical_alloc_section: [[maybe_unused]] if not SEASTAR_ENABLE_ALLOC_FAILURE_INJECTION

Now that internal::critical_alloc_section is defined as volatile
and e042ccf493c698c7337b6e45513cfe5b429bdd81 is reverted,
we can use the [[maybe_unused]] attribute for the dummy
scoped_critical_alloc_section implementation.

Signed-off-by: Benny Halevy <23c997c90eb8537635e9392d48e7af1bf1b2ca22@scylladb.com>

syuu1228/seastar,avikivity/seastar,scylladb/seastar,avikivity/seastar,syuu1228/seastar,avikivity/seastar,scylladb/seastar,syuu1228/seastar,scylladb/seastar