CLOUDSTACK-7959: fixed 'qemu-img convert' compat issue
specifying MinVRVersion as 4.5.0 for the 4.5 branch
Merge branch 'hotfix/4.5-7959' into 4.5
developer: increase disable thresholds global settings for developers

- Increases the disable thresholds for developers
- Removes the use local storage for systemvms

Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>
(cherry picked from commit 314e2daceeeecccdbdc34973d039d16817d2d166)
Signed-off-by: Rohit Yadav <rohit.yadav@shapeblue.com>