Increase VM bring up timeout in exercise scripts
Increase VM bring up timeout in exercise scripts

From 120 to 240 seconds since we are seeing consistent
timeouts.

Change-Id: I50cb36e3002f86fcb2cf48e575862e812b7edff3

stackforge/group-based-policy,stackforge/group-based-policy,noironetworks/group-based-policy,noironetworks/group-based-policy