Update version for 1.6.0

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Open up 1.7 development branch

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Merge branch 'master' of github.com:ncultra/qemu into rcu-for-1.7

merge with upstream master - v 1.6.0