Prevent the external url from including a double http when it has the default value.

package-scripts/gitlab/postinst

@@ -20,9 +20,9 @@ done
 # Try collecting fqdn if it is set correctly
 fqdn=$(/bin/hostname -f)
 if [[ ! -z ${fqdn} ]]; then
-  external_url=${fqdn}
+  external_url="http://${fqdn}/"
 else
-  external_url="http://gitlab.example.com"
+  external_url="http://gitlab.example.com/"
 fi
 # Create a minimal gitlab.rb template if /etc/gitlab/gitlab.rb does not exist.
@@ -30,7 +30,7 @@ if ! [ -e /etc/gitlab/gitlab.rb ] ; then
   mkdir -p /etc/gitlab
   cat > /etc/gitlab/gitlab.rb <<EOF
 # Check and change the external_url to the address your users will type in their browser
-external_url 'http://${external_url}'
+external_url '${external_url}'
 EOF
   chmod 600 /etc/gitlab/gitlab.rb
 fi