fc_sort.py: Use "==" for comparing integers.

"is" is for testing two references are the same object.  The fact that this
worked is specific to the Python implementation.

Signed-off-by: Chris PeBenito <pebenito@ieee.org>

support/fc_sort.py

@@ -108,7 +108,7 @@ class FileContext():
         return 0
 
     def __lt__(self, other):
-        return self._compare(self, other) is -1
+        return self._compare(self, other) == -1
 
     def __str__(self):
         if self.file_type: