Materialized View: fix one of the unit tests
Materialized View: fix one of the unit tests

One of the tests created a base table with 5 primary key columns, but
put only 4 of them in the view. This is not allowed, but prior to fixing
issue #2720 this error was silently ignored. Let's fix the error instead
of relying on this silence.

Signed-off-by: Nadav Har'El <625169824b719df98706d88646d0aae6f368ae4d@scylladb.com>
Message-Id: <20180321094352.22329-1-625169824b719df98706d88646d0aae6f368ae4d@scylladb.com>

duarten/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla,duarten/scylla,avikivity/scylla,avikivity/scylla,avikivity/scylla,scylladb/scylla,duarten/scylla