MT#64445 sync-db helper change central db connection to pair

* Central db connection must not be used when syncing db data
  in the sync-db helper as it causes possible unexpected data
  behaviours when for instance changes in outbound_socket on web01
  immediately applied to the central db node when running
  ngcpcfg apply on web01.
  Therefore, central db connection is switched to the pair
  (localhost:3306) one.

Change-Id: Ie6b17d1bf074deca9cf8a7ac626211af6a43d0e1

Author: sipwiser

helper/sync-db

@@ -30,7 +30,7 @@ my $ngcp_roles = read_ngcp_roles();
 my $ngcp_type = $ngcp_roles->{NGCP_TYPE};
 my $ngcp_is_proxy = $ngcp_roles->{NGCP_IS_PROXY};
 
-my @db_conn_types = qw(central pair local);
+my @db_conn_types = qw(pair local);
 my $db_conn = {};
 my $db_info = {};
 
@@ -180,7 +180,7 @@ sub generic_enum_sync {
     my $peer_pref = shift;
     my $pref_name = shift;
 
-    my $dbh = $db_conn->{central};
+    my $dbh = $db_conn->{pair};
 
     my $sth = $dbh->prepare("select id from voip_preferences where attribute=?");
     $sth->execute($pref_name);