fixed docker installation

Author: githubofkrishnadhas

vmss-linux/cloudinit.conf

@@ -15,6 +15,6 @@ packages:
   - lsb-release
 runcmd:
   - sudo apt-get update
-  - curl -fsSL https://get.docker.com -o get-docker.sh
+  - sudo curl -fsSL https://get.docker.com -o get-docker.sh
   - sudo sh ./get-docker.sh --dry-run
   - docker --info