CLOUDSTACK-6212: Let vm_instance table's ID field be unique and auto_increment
CLOUDSTACK-6212: Let vm_instance table's ID field be unique and auto_increment

`vm_instance` table's id column is unique but does not auto_increment like other
resource tables. The fix simply alter the table's id column to have it
auto_increment which may avoid id conflicts in a multi-master mysql setup.

Signed-off-by: Rohit Yadav <902b9eb5dd62819678163bd5e00fbf0cbc7c264b@shapeblue.com>
(cherry picked from commit e1e5e12aaa649c05f2d5bebe1bdaec00e284dcf0)
Signed-off-by: Rohit Yadav <902b9eb5dd62819678163bd5e00fbf0cbc7c264b@shapeblue.com>

wido/cloudstack,jcshen007/cloudstack,resmo/cloudstack,jcshen007/cloudstack,jcshen007/cloudstack,resmo/cloudstack,GabrielBrascher/cloudstack,wido/cloudstack,GabrielBrascher/cloudstack,resmo/cloudstack,wido/cloudstack,DaanHoogland/cloudstack,DaanHoogland/cloudstack,jcshen007/cloudstack,jcshen007/cloudstack,DaanHoogland/cloudstack,wido/cloudstack,wido/cloudstack,resmo/cloudstack,wido/cloudstack,DaanHoogland/cloudstack,DaanHoogland/cloudstack,DaanHoogland/cloudstack,jcshen007/cloudstack,resmo/cloudstack,GabrielBrascher/cloudstack,wido/cloudstack,GabrielBrascher/cloudstack,GabrielBrascher/cloudstack,resmo/cloudstack,jcshen007/cloudstack,resmo/cloudstack,GabrielBrascher/cloudstack,GabrielBrascher/cloudstack,DaanHoogland/cloudstack