Fixed init.d script not working on OS X

-s flag of su doesn't work correctly on some systems, loging in the user
and not running the requested command. By moving the bash shell init
inside the su command we avoid the issue

CHANGELOG

@@ -35,6 +35,7 @@ v 8.5.0 (unreleased)
   - Fixed logo animation on Safari (Roman Rott)
   - Hide remove source branch button when the MR is merged but new commits are pushed (Zeger-Jan van de Weg)
   - In seach autocomplete show only groups and projects you are member of
+  - Fix: init.d script not working on OS X
 
 v 8.4.4
   - Update omniauth-saml gem to 1.4.2

lib/support/init.d/gitlab

@@ -49,7 +49,7 @@ test -f /etc/default/gitlab && . /etc/default/gitlab
 
 # Switch to the app_user if it is not he/she who is running the script.
 if [ `whoami` != "$app_user" ]; then
-  eval su - "$app_user" -s $shell_path -c $(echo \")$0 "$@"$(echo \"); exit;
+  eval su - "$app_user" -c $(echo \")$shell_path -l -c \'$0 "$@"\'$(echo \"); exit;
 fi
 
 # Switch to the gitlab path, exit on failure.