FIX: modification of complementary attributes in commercial proposals

[am97]

FIX: modification of complementary attributes in commercial proposals

Problem

We have some complementary attributes in /comm/admin/propal_extrafields.php in our Dolibarr 16.0.5 instance. When trying to modify these attributes on any commercial proposal, we get a blank page. For example:

Here, we click on the pen icon next to % Facturé, we select a value, then we click on MODIFY. We get a blank page, and the following error in the logs:

PHP Fatal error:  Uncaught Exception: Serialization of 'PgSql\Connection' is not allowed in /var/www/html/core/lib/functions.lib.php:1166
Stack trace:
#0 /var/www/html/core/lib/functions.lib.php(1166): serialize()
#1 /var/www/html/comm/propal/card.php(1470): dol_clone()
#2 {main}

Fix

This PR replaces the dol_clone function by the one in the 17.0 branch, in order to have the method 2 (Full isolation method keeping only scalar and array properties). There should be no side effects, but if you want to be extra sure, I can keep the old conditions (ie. if (empty($native)) instead of if ($native == 0) and if ($tmpsavdb) instead of if (!empty($tmpsavdb))).

Then, I use the method 2 in the dol_clone that caused the PHP error in comm/propal/card.php.

I tested this fix in our instance and everything seems fine.