Increase the command timeout to get cico node

We can't have more than 5 requests/sessions (still active)
in the last 5 minutes. So, we need to increase the timeout
from 6m to 15m.

Change-Id: I11ad7c193540f23064a35131476f3dcd7250a98e

ci-scripts/get-node.sh

@@ -65,7 +65,7 @@ $WORKSPACE/bin/cico node get \
     --arch x86_64 \
     --release $CENTOS_RELEASE \
     --count 1 \
-    --retry-count 6 \
+    --retry-count 15 \
     --retry-interval 60 \
     -f csv | sed "1d" > $WORKSPACE/provisioned.csv