Fix ImportError in contrail-alarm-notify

The entry point for contrail-alarm-notify is opserver/alarm_notify.py
There is a module named opserver.py in opserver package. Therefore, the
following statement looks for sandesh.viz.constants in opserver.py
instead of the opserver package.
from opserver.sandesh.viz.constants import UVE_MAP

Change-Id: Ie238fbae3a5195e47bde5edac5e3a6d5f619f17a
Closes-Bug: #1562077
(cherry picked from commit 89e583c)

src/opserver/alarm_notify.py

@@ -23,7 +23,7 @@
 from email.MIMEMultipart import MIMEMultipart
 from email.MIMEText import MIMEText
 
-from opserver.sandesh.viz.constants import UVE_MAP
+from sandesh.viz.constants import UVE_MAP
 
 
 class ContrailAlarmInfo(object):