PYCBC-243: iops/select: Use rich comparison methods rather than __cmp__

This fixes an issue where tests would fail under Python 3. The __cmp__
method is not used in Python 3, which rather expects to find the rich
comparison operations
(https://docs.python.org/2/reference/datamodel.html#object.__lt__)

Change-Id: I4c0cdb3d7bd96bbefdec58e65ddc2b382acca458
Reviewed-on: http://review.couchbase.org/37083
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Volker Mische <volker.mische@gmail.com>

couchbase/iops/select.py

@@ -51,9 +51,13 @@ def deactivate(self):
     def active(self):
         return self.state == PYCBC_EVSTATE_ACTIVE
 
-    def __cmp__(self, other):
-        return cmp(self.exptime, other.exptime)
-
+    # Rich comparison operators implemented - __cmp__ not used in Py3
+    def __lt__(self, other): return self.exptime < other.exptime
+    def __le__(self, other): return self.exptime <= other.exptime
+    def __gt__(self, other): return self.exptime > other.exptime
+    def __ge__(self, other): return self.exptime >= other.exptime
+    def __ne__(self, other): return self.exptime != other.exptime
+    def __eq__(self, other): return self.exptime == other.exptime
 
 
 class SelectIOPS(object):