Updated openstack/openstack
Project: openstack-dev/devstack  121d65023b822fd4285d315386eedd023cbf223e
null
Add 'bc' to files/apts/general

After commit def4c141, "bc" command is used in stack.sh,
but 'bc' command is not available in very minimal Ubuntu
installation (without any tasks installed).
We need to add 'bc' to required package list.

Closes-Bug: #1272914
Change-Id: I5797707e8eaa9dd2a21d1a1fc3af028d1951a2ee