Convert SetInstanceParams to concurrency
Convert SetInstanceParams to concurrency

Grab a lock for the instance we're working on, and update its params.

Reviewed-by: iustinp


mbakke/ganeti,ganeti/ganeti,andir/ganeti,grnet/snf-ganeti,apyrgio/ganeti,dimara/ganeti,apyrgio/ganeti,apyrgio/snf-ganeti,andir/ganeti,ganeti-github-testing/ganeti-test-1,leshchevds/ganeti,onponomarev/ganeti,grnet/snf-ganeti,leshchevds/ganeti,onponomarev/ganeti,dimara/ganeti,yiannist/ganeti,ganeti-github-testing/ganeti-test-1,yiannist/ganeti,leshchevds/ganeti,bitemyapp/ganeti,ganeti/ganeti,apyrgio/snf-ganeti,mbakke/ganeti,mbakke/ganeti,ganeti/ganeti,bitemyapp/ganeti,yiannist/ganeti,andir/ganeti