Do not write port config for apache twice (bnc#897996)

We were defining the template twice, which resulted in the file being
written twice, including once with some non-valid config.

Instead, just override the variable we need in the template the second
time.

https://bugzilla.suse.com/show_bug.cgi?id=897996
(cherry picked from commit 75a98648b9b19c8319827bc6343208bd55008593)