Make NIC VLAN queryable
Make NIC VLAN queryable

Add an additional query field which makes it possible to query for
VLANs of instance NICs.

Signed-off-by: Thomas Thrainer <98bdeac947eb8ca18146e9ce7f092788ec242cd1@google.com>
Reviewed-by: Hrvoje Ribicic <be5828fca31f89218048bec4189e30a581aa65da@google.com>

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