Add HA option and minor fixes

This commit adds the --ha option which will
install the osm-ha bundle instead of the standard
osm bundle.

Additionally this commit includes the following
fixes:
- change the use of route to ip route which is
preinstalled in Ubuntu Desktop also.
- Change final command of post install osmclient
message
- Change post install osmclient message to be
only shown during install and not uninstall.
- Fix the deletion of the wrong model in uninstall
- Pining Juju snap to 2.7/stable

Change-Id: Iccf3bda7ec2f9a2279e5535d819e2a1968a59687
Signed-off-by: Dominik Fleischmann <dominik.fleischmann@canonical.com>
diff --git a/installers/install_osm.sh b/installers/install_osm.sh
index 4ede419..3659354 100755
--- a/installers/install_osm.sh
+++ b/installers/install_osm.sh
@@ -75,6 +75,7 @@
     echo -e "     [--lxd <yaml path>]:         Takes a YAML file as a parameter with the LXD Cloud information (--charmed option)" 
     echo -e "     [--lxd-cred <yaml path>]:    Takes a YAML file as a parameter with the LXD Credentials information (--charmed option)"
     echo -e "     [--microstack]:              Installs microstack as a vim. (--charmed option)"
+    echo -e "     [--ha]:                      Installs High Availability bundle. (--charmed option)"
     echo -e "     [--tag]:                     Docker image tag"
 
 }