Eliminate redundant code obsoleted by full_clean()

Change-Id: I4d629c82101147dfc7b007e749b99ed5685b3c2a
diff --git a/containers/chameleon/Dockerfile.chameleon b/containers/chameleon/Dockerfile.chameleon
index 103e773..cf9deeb 100644
--- a/containers/chameleon/Dockerfile.chameleon
+++ b/containers/chameleon/Dockerfile.chameleon
@@ -13,7 +13,7 @@
 # limitations under the License.
 
 # xosproject/chameleon
-FROM xosproject/xos-base:2.1.11
+FROM xosproject/xos-base:2.1.12
 
 # xos-base already has protoc and dependencies installed