Fix sorting bug in LUQueryGroups
Fix sorting bug in LUQueryGroups

In LUQueryGroups.Exec(), NiceSort was being applied to group UUIDs, and
not to group names. We use a temporary name to UUID map to sort the list
of UUIDs by group name instead.

Signed-off-by: Adeodato Simo <16293852a0900193fe70fa7d24f714f37ba99a56@google.com>
Reviewed-by: Guido Trotter <f62ca4d5358bdaeef0e50e57f9f7e231de63727e@google.com>

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