Small refactoring for packer scripts

* Get rid of formula version variable and use MCP_VERSION instead
* Remove docker images pull
* Remove adding of jenkins theme b/c it's already inside docker image
* Move flag for jenkins in docker to /opt

Closes-task: #PROD-24048 (PROD:24048)
Change-Id: I41a1c4771d9cf890bd371264a35727ded6fc52a8
diff --git a/mirror-image/run.example.sh b/mirror-image/run.example.sh
index a27455a..acaea28 100755
--- a/mirror-image/run.example.sh
+++ b/mirror-image/run.example.sh
@@ -20,7 +20,6 @@
 export CLUSTER_NAME="mcp-offline"
 
 export MCP_VERSION="proposed"
-export FORMULA_VERSION="proposed"
 
 BINARY_MCP_VERSION="proposed"
 export UBUNTU_BASEURL="http://mirror.mirantis.com/${BINARY_MCP_VERSION}/ubuntu/"
diff --git a/mirror-image/scripts/mirrors.sh b/mirror-image/scripts/mirrors.sh
index 67cf90c..bdf686e 100644
--- a/mirror-image/scripts/mirrors.sh
+++ b/mirror-image/scripts/mirrors.sh
@@ -26,7 +26,7 @@
 # Those would prevent failures for 2018q3+ model releases, where
 # 'system.linux.system.repo.mcp.apt_mirantis.update.xxx' enabled by default
 pushd /srv/volumes/aptly/public/
-  CUR_V=$(salt-call pillar.get _param:apt_mk_version --out text | awk '{print $2}')
+  CUR_V=$(salt-call pillar.get _param:mcp_version --out text | awk '{print $2}')
   mkdir -p update
   ln -s ../${CUR_V} update/${CUR_V} || true
 popd
diff --git a/mirror-image/template.json b/mirror-image/template.json
index dc62f90..3c13117 100644
--- a/mirror-image/template.json
+++ b/mirror-image/template.json
@@ -10,7 +10,6 @@
     "cluster_model_ref": "{{ env `CLUSTER_MODEL_REF` }}",
     "cluster_name": "{{ env `CLUSTER_NAME` }}",
     "bs_hostname": "apt01",
-    "formula_version": "{{ env `FORMULA_VERSION` }}",
     "mcp_version": "{{ env `MCP_VERSION` }}",
     "ubuntu_baseurl": "{{ env `UBUNTU_BASEURL` }}",
     "saltstack_gpg": "{{ env `SALTSTACK_GPG` }}",
@@ -53,7 +52,6 @@
         "CLUSTER_MODEL_REF={{ user `cluster_model_ref` }}",
         "CLUSTER_NAME={{ user `cluster_name` }}",
         "BS_HOSTNAME={{ user `bs_hostname` }}",
-        "FORMULA_VERSION={{ user `formula_version` }}",
         "UBUNTU_BASEURL={{ user `ubuntu_baseurl` }}",
         "SALTSTACK_GPG={{ user `saltstack_gpg` }}",
         "SALTSTACK_REPO={{ user `saltstack_repo` }}",