Error handling for instance config file creation
Error handling for instance config file creation

Wrap error handling around creating the instance config file.

Reviewed-by: iustinp



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