Adding checking around the monotonic import

Change-Id: I88c05ecf7ce0caade4ff00630c65c9b7eb690fbd
Closes-Bug: 1476588

oslo_utils/timeutils.py

@@ -23,7 +23,13 @@ import time
 
 from debtcollector import removals
 import iso8601
-from monotonic import monotonic as now  # noqa
+try:
+    from monotonic import monotonic as now  # noqa
+except RuntimeError:
+    try:
+        now = time.monotonic
+    except AttributeError:
+        now = time.time
 from pytz import timezone
 import six