Fix validation to allow pass 0 values as they represent all hosts

[jonatas]

It fixes #155 as we use zero values to represent all hosts. we cannot validate < 1 but < 0 to allow us to use of all hosts and get a random host.

[CLAassistant]

All committers have signed the CLA.

[Hadrien-Cornier]

Thanks for the fix, I just tested it and it seems to work

What I did :
hadrien@****:~/go_projects/src/github.com/timescale/tsbs$ git checkout 155-fix-nhosts-for-all-queries
hadrien@****:~/go_projects/src/github.com/timescale/tsbs$ make
command :
hadrien@****:~/go_projects/src/github.com/timescale/tsbs$ $GOBIN/tsbs_generate_queries --use-case="devops" --seed=123 --scale=2000 --timestamp-start="2021-03-01T00:00:00Z" --timestamp-end="2021-03-06T00:00:00Z" --queries=1000 --query-type="high-cpu-all" --format="cratedb" > /data/research/benchmark-ts-databases/crate/debug_cratedb
output :
CrateDB CPU over threshold, all hosts: 1000 points
command :
hadrien@****:~/go_projects/src/github.com/timescale/tsbs$ $GOBIN/tsbs_generate_queries --use-case="devops" --seed=123 --scale=2000 --timestamp-start="2021-03-01T00:00:00Z" --timestamp-end="2021-03-06T00:00:00Z" --queries=1000 --query-type="high-cpu-all" --format="mongo" > /data/research/benchmark-ts-databases/mongo/debug_mongodb
output :
Mongo CPU over threshold, all hosts: 1000 points

[jonatas]

Yay! thanks for reporting @Hadrien-Cornier 🙇