LUCreateInstance: accept mac = VALUE_GENERATE
LUCreateInstance: accept mac = VALUE_GENERATE

VALUE_GENERATE is handled exactly the same as VALUE_AUTO and the mac
address is generated randomly.

Forward-port-of: r1886, Reviewed-by: iustinp

Reviewed-by: imsnah


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