Remove iso8601 dependency

The parse_isotime() from oslo.utils does exactly that in a slightly
better way, so no need to use that one here.

Change-Id: I1bf7f60f2bf8e5848a2a1f3a2a55b6d379641900

heat/engine/constraint/common_constraints.py

@@ -12,12 +12,12 @@
 #    under the License.
 
 import croniter
-import iso8601
 import netaddr
 import pytz
 import six
 
 from oslo_utils import netutils
+from oslo_utils import timeutils
 
 from heat.common.i18n import _
 from heat.engine import constraints
@@ -59,7 +59,7 @@ class ISO8601Constraint(object):
 
     def validate(self, value, context):
         try:
-            iso8601.parse_date(value)
+            timeutils.parse_isotime(value)
         except Exception:
             return False
         else:

requirements.txt

@@ -9,7 +9,6 @@ cryptography>=1.0 # Apache-2.0
 eventlet>=0.17.4
 greenlet>=0.3.2
 httplib2>=0.7.5
-iso8601>=0.1.9
 keystonemiddleware>=2.0.0
 kombu>=3.0.7
 lxml>=2.3