vcs.Canvas.isinfile return value consistency

[chaosphere2112]

@doutriaux1 @chaosphere2112 Should we make this thing return 0 when it doesn't find what it's looking for?
I would think that we should do that to be consistent.

Migrated from: CDAT/cdat#2109

[ghost]

@doutriaux1 @chaosphere2112, on further inspection it looks like this doesn't even work:

>>> a=vcs.init()
>>> box=a.getboxfill()
>>> a.scriptobject(box, 'deft_box.py')
>>> a.scriptobject(box, 'deft_box') # json format
>>> a.isinfile(box, 'deft_box.json')
>>> a.isinfile(box, 'deft_box.py')

One or both of these should return 1, but neither returns anything.
I think we either have to scrap this or re-write the function.

I can make it work for .py files by changing the line:
key = gm + '_' + nm + '(' to key = '__' + gm + '__' + nm