Handle undefined resource names

[dsschult]

If the resource name classad exists but is set to the value classad.Value.Undefined (we appear to have this when flocking to CHTC directly), allow processing to continue.

Example of classads:

LastRemoteHost = "slot1_30@e2588.chtc.wisc.edu"
LastRemotePool = "cm.chtc.wisc.edu"
MATCH_EXP_JOBGLIDEIN_ResourceName = "Local Job"
MachineAttrGLIDEIN_ResourceName0 = undefined

Before this PR, it would look at MachineAttrGLIDEIN_ResourceName0 first and return the undefined value, then break later in the code. Now it says it's a local job, which seems better?

I leave it up to OSG to decide if they want CHTC to be counted.

[mwestphall]

Hi @dsschult , I've left a couple comments on this PR.

[mwestphall]

Suggested change

	resource_name = classad.get(attr)
	resource_name = classad.eval(attr)

[mwestphall]

Eval is more robust than get here in case the classads are not literal values

[mwestphall]

Suggested change

	if resource_name and resource_name not in (classadLib.Value.Undefined, classadLib.Value.Error):
	if resource_name and resource_name is not classadLib.Value.Undefined and resource_name is not classadLib.Value.Error:

[mwestphall]

Per the HTCondor dev team, you need to use identity comparisons to check against classadLib.Value values since they're just integers

[mwestphall]

Requesting a couple changes