Changing version from 1.15.0-SNAPSHOT to 2.0.0-SNAPSHOT.

Change-Id: I61a586cfc769275db78f4059a630ab0e0f87c6e7
diff --git a/onos.defs b/onos.defs
index 502b4ad..4d44fee 100644
--- a/onos.defs
+++ b/onos.defs
@@ -1,6 +1,6 @@
 ONOS_ORIGIN = 'ONOS Community'
 ONOS_GROUP_ID = 'org.onosproject'
-ONOS_VERSION = '1.15.0-SNAPSHOT'
+ONOS_VERSION = '2.0.0-SNAPSHOT'
 DEFAULT_APP_CATEGORY = 'Utility'
 ONOS_ARTIFACT_BASE = 'onos-'
 APP_PREFIX = ONOS_GROUP_ID + '.'