select count(1) from (select 1 from Y .. limit X) can have a longer
runtime, depending on order of rows in table Y.
to better limit the runtime, X is reduced from 1000 to 10.
the UI will show now "used by 10+ contracts" instead of
"used by 1000+ contracts".
Change-Id: I028b0569cd5f3325d4bd6bed314517b061e4659b