Retry more aggressively to mount EFS

If EFS is not mounted the instance should be considered unhealthy.
At the moment we don't have a way of doing it, so we just retry more
to minimize it.

Change-Id: I151b4fe40f515a016e12c4ece93ae1c14c012552
diff --git a/dual-master/cf-cluster.yml b/dual-master/cf-cluster.yml
index ff1f187..8ace0a8 100644
--- a/dual-master/cf-cluster.yml
+++ b/dual-master/cf-cluster.yml
@@ -159,7 +159,7 @@
           echo $EC2_REGION >> /home/ec2-user/echo.res
           echo $DIR_SRC >> /home/ec2-user/echo.res
           echo $DIR_TGT >> /home/ec2-user/echo.res
-          MAX_RETRIES=5
+          MAX_RETRIES=20
           for i in $(seq 1 $MAX_RETRIES); do
             echo "Mounting EFS volume ($i/$MAX_RETRIES)..."
             `mount -t nfs4 -o nfsvers=4.1,hard,timeo=600,retrans=2 $DIR_SRC:/ $DIR_TGT >> /home/ec2-user/echo.res` \