Master branch broken because of incorrect use of variable

[shrinandj]

Switching to on-demand instances from spot-instances is currently broken because of the following:

2019-03-26T05:38:29 ERROR aws_minion_manager MainThread: Failed while checking instances in ASG: global name 'spot_price' is not defined
Traceback (most recent call last):
  File "/src/cloud_provider/aws/aws_minion_manager.py", line 593, in minion_manager_work
    self.update_scaling_group(asg_meta, new_bid_info)
  File "/src/cloud_provider/aws/aws_minion_manager.py", line 330, in update_scaling_group
    self.create_lc_on_demand(new_lc_name, launch_config)
  File "/usr/local/lib/python2.7/site-packages/retrying.py", line 49, in wrapped_f
    return Retrying(*dargs, **dkw).call(f, *args, **kw)
  File "/usr/local/lib/python2.7/site-packages/retrying.py", line 212, in call
    raise attempt.get()
  File "/usr/local/lib/python2.7/site-packages/retrying.py", line 247, in get
    six.reraise(self.value[0], self.value[1], self.value[2])
  File "/usr/local/lib/python2.7/site-packages/retrying.py", line 200, in call
    attempt = Attempt(fn(*args, **kwargs), attempt_number, False)
  File "/src/cloud_provider/aws/aws_minion_manager.py", line 270, in create_lc_on_demand
    SpotPrice=spot_price,
NameError: global name 'spot_price' is not defined