method list_sizes() on driver object does not accept location

[RobertH1993]

Summary

method list_sizes() on driver object does not accept location parameter. The docs states that it should accept a location parameter: https://libcloud.readthedocs.io/en/stable/compute/api.html#libcloud.compute.base.NodeDriver.list_sizes

Detailed Information

Tried to get all the sizes through the digitalOcean driver, filtering on a certain location. I pass a NodeLocation object (retrieved from driver with function list_locations()) into list_sizes(). After that i get the error:

list_sizes() takes 1 positional argument but 2 were given

Expected to get a list of sizes available for the given location as stated in the documentation.

Fix

The api of digitalOcean returns a region key for every returned size, this key holds a list with all regions this size is available. Accept location parameter in list_sizes() and check if the NodeLocation.id is in regions.

[RobertH1993]

Just made a pull_request, tested locally works fine :)
#1456