Make sure we send a return code when the command fails

Click does not let the return code pass through. So, we explicitly use sys.exit(). pallets/click#747

axltempl/drupal.py

@@ -6,6 +6,7 @@
 import os
 import pkgutil
 import shutil
+import sys
 
 import click
 
@@ -99,14 +100,14 @@ def main(
  f'The "{directory}" directory already exists.'
  + "Please delete it before running or use the -f option."
  )
- return 2
+ sys.exit(2)
  util.write_warning(f'Removing "{directory}" directory...')
  try:
  shutil.rmtree(directory)
  except OSError as err:
  util.write_error(f'Failed deleting the "{directory}" directory')
  util.write_error(str(err))
- return 2
+ sys.exit(2)
 
  os.mkdir(directory)
  os.chdir(directory)