fix(cloud-config): Fix checkout of exosphere version

This commit removes the use of `--checkout` inadvertently kept after
updating the format of `cloud-config` in 7dbe8c0 ("fix(cloud-config): Re-introduce MorpoCloud specific changes", 2025-02-01)

The `--checkout` parameter is specific to `ansible-playbook` and can not
be used with `git`.

cloud-config

@@ -51,12 +51,13 @@ rm -rf /opt/instance-config-mgt
 #   "{instance-config-mgt-repo-url}" \
 #   /opt/instance-config-mgt
 
-exosphere_sha="61891a755ee0a4f9d15b586d60477814885656fc" # morpho-cloud-portal-2025.01.29-5f7a4c38
 retry git clone \
-  --checkout="$exosphere_sha" \
   "https://github.com/MorphoCloud/exosphere.git" \
   /opt/instance-config-mgt
 
+exosphere_sha="61891a755ee0a4f9d15b586d60477814885656fc" # morpho-cloud-portal-2025.01.29-5f7a4c38
+(cd /opt/instance-config-mgt && git reset --hard $exosphere_sha)
+
 ansible-playbook \
   -i /opt/instance-config-mgt/ansible/hosts \
   -e "{\"guac_enabled\":true,\"gui_enabled\":true,\"ansible_python_interpreter\":\"/opt/ansible-venv/bin/python\"}" \