Update client_ipsec.secrets.j2 (#414)

Fix filename in client ipsec_user.secrets

roles/vpn/templates/client_ipsec.secrets.j2

@@ -1,5 +1,5 @@
 {% if Win10_Enabled is defined and Win10_Enabled == "Y" %}
-{{ IP_subject_alt_name }} : RSA {{ IP_subject_alt_name }}_{{ item }}.key
+{{ IP_subject_alt_name }} : RSA {{ item }}.key
 {% else %}
-{{ IP_subject_alt_name }} : ECDSA {{ IP_subject_alt_name }}_{{ item }}.key
+{{ IP_subject_alt_name }} : ECDSA {{ item }}.key
 {% endif %}