override package name when vendor repo is enabled

defaults/main.yml

@@ -2,3 +2,4 @@
 postgres_repository_enabled: False
 postgres_version: 10
 postgres_repository_filename: "Postgresql-{{ postgres_version | regex_replace('\\.') }}"
+postgres_packagename: postgresql-server

tasks/prepare.yml

@@ -9,7 +9,9 @@
       gpgcheck: yes
       enabled: yes
       gpgkey: "https://download.postgresql.org/pub/repos/yum/RPM-GPG-KEY-PGDG-{{ postgres_version }}"
-    when: postgres_repository_enabled
 
+  - set_fact:
+      postgres_packagename: "postgresql{{ postgres_version | regex_replace('\\.') }}-server"
   become: True
   become_user: root
+  when: postgres_repository_enabled