Merge branch 'feat_add_default_env' into 'master'

Add dev as the deafult env

See merge request !14

.gitlab-ci.yml

 image: gitlab.rc.uab.edu:4567/rc/packer-openstack-hpc-image:latest
 
 variables:
+  TARGET_ENV: "dev"
   ANSIBLE_REMOTE_TMP: "/tmp"
   OS_REGION_NAME: "bhm1"
   OS_INTERFACE: "public"
@@ -9,8 +10,6 @@ variables:
   OS_AUTH_URL: "https://keystone.cloud.rc.uab.edu:5000/v3"
   TF_ROOT: ${CI_PROJECT_DIR}/
   TF_VAR_external_network: "xdmod-packer-dmznet"
-  TF_VAR_flavor: "m1.medium"
-  TF_VAR_data_volume: "xdmod-mysql-db-migration"
   GIT_SUBMODULE_STRATEGY: "recursive"
   GIT_SUBMODULE_UPDATE_FLAGS: "--force"