Change naming of Charmed Installer Parameters

The naming for the following parameters in the
Charmed installer has been changed:

kubeconfig -> k8s
controller -> vca
lxd-cloud -> lxd
lxd-credentials -> lxd-cred

Change-Id: Id760cd332c4be76a3cf45a108d7448387a78a94a
Signed-off-by: Dominik Fleischmann <dominik.fleischmann@canonical.com>
diff --git a/installers/charmed_install.sh b/installers/charmed_install.sh
index b89855f..62fa547 100755
--- a/installers/charmed_install.sh
+++ b/installers/charmed_install.sh
@@ -21,10 +21,10 @@
     while [ $# -gt 0 ] ; do
         case $1 in
             --bundle) BUNDLE="$2" ;;
-            --kubeconfig) KUBECFG="$2" ;;
-            --controller) CONTROLLER="$2" ;;
-            --lxd-cloud) LXD_CLOUD="$2" ;;
-            --lxd-credentials) LXD_CREDENTIALS="$2" ;;
+            --k8s) KUBECFG="$2" ;;
+            --vca) CONTROLLER="$2" ;;
+            --lxd) LXD_CLOUD="$2" ;;
+            --lxd-cred) LXD_CREDENTIALS="$2" ;;
             --microstack) MICROSTACK=y ;;
             --tag) TAG="$2" ;;
         esac