This patch sets the filename when the new qapi backend
init from opts.

The previous patch and discussions as link below:

http://patchwork.ozlabs.org/patch/243896/



If anyone who have better idea to fix this please let
me know your suggestions.

Signed-off-by: Lei Li <lilei@linux.vnet.ibm.com>
Message-id: 1369132079-11377-3-git-send-email-lilei@linux.vnet.ibm.com
Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>