build: always add subdirs

bash-completion/meson.build

@@ -1,3 +1,4 @@
+if get_option('bash-completions')
 bash_completions = [
   'openrc',
   'openrc-service-script',
@@ -8,3 +9,4 @@ bash_completions = [
 
 install_data(bash_completions,
   install_dir : get_option('datadir') / 'bash-completion/completions')
+endif