Remove version pinning from examples

These pinned versions are frequently removed from Ubuntu's repositories,
leading to broken tests.  Removing them will expose us to breakage from
unexpected updates, but will avoid issues with removed packages.

Change-Id: I30bf993fa20f0054ee77eb47086a784f6d02d2ac

examples/basic/HostSystem.yaml

@@ -74,8 +74,8 @@ data:
       - curl
       - jq
     required:
-      docker: docker-engine=1.13.1-0~ubuntu-xenial
-      socat: socat=1.7.3.1-1
+      docker: docker-engine
+      socat: socat
   validation:
     pod_logs:
       image: busybox:1.28.3

examples/complete/HostSystem.yaml

@@ -71,10 +71,10 @@ data:
         =Fm3p
         -----END PGP PUBLIC KEY BLOCK-----
     additional:
-      - ceph-common=10.2.9-0ubuntu0.16.04.1
+      - ceph-common
       - curl
       - jq
     required:
-      docker: docker-engine=1.13.1-0~ubuntu-xenial
-      socat: socat=1.7.3.1-1
+      docker: docker-engine
+      socat: socat
 ...

tools/gate/config-templates/site-config.yaml

@@ -103,10 +103,10 @@ data:
         =Fm3p
         -----END PGP PUBLIC KEY BLOCK-----
     additional:
-      - ceph-common=10.2.9-0ubuntu0.16.04.1
+      - ceph-common
     required:
-      docker: docker-engine=1.13.1-0~ubuntu-xenial
-      socat: socat=1.7.3.1-1
+      docker: docker-engine
+      socat: socat
 ---
 schema: promenade/Kubelet/v1
 metadata: