If 'virNumaGetHostNodeset()' fails then the error path will try to free
uninitialized pointer mem_mask. Introduced by commit af2a1f05.
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>
(cherry picked from commit 77a9dc0b)
Signed-off-by: NPavel Hrdina <phrdina@redhat.com>