before this change, we use `round(random.random(), 5)` for
the value of `bloom_filter_fp_chance` config option. there are
chances that this expression could return a number lower or equal
to 6.71e-05.
but we do have a minimal for this option, which is defined by
`utils::bloom_calculations::probs`. and the minimal false positive
rate is 6.71e-05.
we are observing test failures where the we are using 0 for
the option, and scylla right rejected it with the error message of
```
bloom_filter_fp_chance must be larger than 6.71e-05 and less than or equal to 1.0 (got 0)
```.
so, in this change, to address the test failure, we always use a number
slightly greater or equal to a number slightly greater to the minimum to
ensure that the randomly picked number is in the range of supported
false positive rate.
Fixes#13313
Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
Closes#13314
33f4012eeb