BuildableItems (Subtasks) are miscounted in the queue

Expected:
When a labeled job is in the queue its nodeprovisioner should report excess load and provision a new node. The "free roaming" nodeprovisioner should report no load and not provision a new node.

Actual:
In addition to JENKINS-25207 (The free roaming nodeprovisioner spawns nodes even though the job is labeled), it is possible for the appropriate nodeprovisioner to not report load because of use of == on the label.

Technical:
Labels are compared in a number of places with == instead of equals

Additionally af55e5345628d31f49390e11a473079bed750fd9, modified the behaviour of the "free roaming" label in the queue. This results in spawning nodes for "free roaming" jobs, even when none exist.

I have included a pull request that resolves these issues.