Remove unneeded code

Initialization of node.crowbar["crowbar"] and
node.crowbar["crowbar"]["network"] is already done in
NodeObject.create_new_role().
The NodeObject.allocated method was removed

Use allocated? instead. This seems to be collateral damage from
commit b12b969f.
Initialize "allocated" attribute when creating the node object

Apart from being somewhat cleaner also avoids breaking the true/false
convention for the NodeObject.allocated? method.
Make allocated? behave according to ruby conventions

'?' methods should only return a boolean
Merge pull request #1030 from rhafer/fix-transition

The NodeObject.allocated method was removed