adjust the width of host info-container

the layout is wrong in firefox, fix it.

Signed-off-by: ShaoHe Feng <shaohef@linux.vnet.ibm.com>
VM template: add disk size error message

The schema checker needs to report an error message when the disk size
is less than 1GB. Currently this message is missing, so it reports an
KeyError. This patch adds the error message.

How to trigger this bug:
1. In Web UI, create a template as usual.
2. Edit the template, define the disk size as 0.5.

v2:
  v1 adds the error to "disks", but the error is not raised against it.
  v2 correctly adds the error message to the "size" constraint.

Signed-off-by: Zhou Zheng Sheng <zhshzhou@linux.vnet.ibm.com>