Combine the two _CreateBlockDevOnXXX functions
Combine the two _CreateBlockDevOnXXX functions

Since only two boolean parameters differ between these two functions, we
combine them as to have less code duplication. This will be needed in
the future as we will need to split off the recursive part off.

Reviewed-by: ultrotter

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