FIX: fix installer

install_python_client.sh

@@ -5,17 +5,16 @@ dir_name="temp_dir"
 default_api_url="https://gitlab.indiscale.com/fdo/fdo-manager-service/-/raw/main/api/src/main/resources/api.yaml"
 
 # Check openapi-python-client and install if necessary
-if [ "$(which openapi-python-client)" == "" ]
-then
+if [ -z "$(which openapi-python-client)" ]; then
   echo 'openapi-python-client not found, installing'
   pip install openapi-python-client
 fi
 
 # Create temporary folder
-if [[ -d "$dir_name" ]]
+if [ -d "$dir_name" ]
 then
   echo 'Temporary folder already exists, aborting.'
-  exit
+  exit 0
 else
   echo 'creating temporary folder'
   mkdir $dir_name