Sourcing envDefaults in onos-prepare-release

Change-Id: I43479a35ff5fa5a57647355b13989ac5c733d5f5

@@ -29,5 +29,6 @@ git checkout $BRANCH
 git tag -l | grep -q $ONOS_VERSION && { echo "ERROR: Version already exists"; exit -1; }
 git tag -l | grep -q $ONOS_VERSION && { echo "ERROR: Version already exists"; exit -1; }
 
 
 export ONOS_ROOT=$DIR
 export ONOS_ROOT=$DIR
+. $ONOS_ROOT/tools/build/envDefaults
 exec bash -i
 exec bash -i