The blocked task detector introduced in
113ed9e963 was seeing
the initialization phase of perf_ssttable as a blocked
task.
Tranform this part of the code in a futurized loop
to make to blocked task detector happy.
Signed-off-by: Benoît Canet <benoit@scylladb.com>
Message-Id: <20170413132506.17806-1-benoit@scylladb.com>