haproxy: fix pg backend name to avoid conflict

Author: immerrr

config/haproxy.cfg

@@ -34,6 +34,6 @@ backend bk_db
     option httpchk GET /flycheck/role
     http-check expect string primary
     http-check disable-on-404
-    server-template pg 10 $PRIMARY_REGION.$FLY_APP_NAME.internal:5433 check port 5500 resolvers flydns resolve-prefer ipv6 init-addr none on-marked-down shutdown-sessions
+    server-template pgprimaryregion 10 $PRIMARY_REGION.$FLY_APP_NAME.internal:5433 check port 5500 resolvers flydns resolve-prefer ipv6 init-addr none on-marked-down shutdown-sessions
     server-template pg 10 $FLY_APP_NAME.internal:5433 check port 5500 resolvers flydns resolve-prefer ipv6 init-addr none on-marked-down shutdown-sessions
     server pg [$PG_LISTEN_ADDRESS]:5433 check backup port 5500 on-marked-down shutdown-sessions