Add curl package to puppet nodepool element

puppet element calls install_puppet.sh script from system-config repo,
which depends on either curl or wget being installed in the system. Some
minimal images like debian jessie or ubuntu xenial miss those packages
and cause puppet element to fail when building the image.

Change-Id: Ic5124906b19b82d134a611e68fc7c5dd6fc88702

nodepool/elements/puppet/element-deps

@@ -1,3 +1,4 @@
 cache-url
 openstack-repos
+package-installs
 source-repositories

nodepool/elements/puppet/package-installs.yaml

@@ -0,0 +1 @@
+curl:

nodepool/elements/puppet/pkg-map

@@ -0,0 +1,10 @@
+{
+  "family": {
+    "gentoo": {
+      "curl": "net-misc/curl"
+    }
+  },
+  "default": {
+    "curl": "curl"
+  }
+}