Indexing an only partition key component is not allowed (because it would be redundant), but it should be allowed to index one of several partition key components. We had a bug in that case: the underlying materialized view we created had the same column as both a partition key and a clustering key, which resulted in an assertion failure. This patch fixes that. Fixes #3404. Signed-off-by: Nadav Har'El <nyh@scylladb.com> Message-Id: <20180501121544.22869-1-nyh@scylladb.com>