Fix #3188 SQL error if qty or discount is not a number on proposal add line

htdocs/comm/propal/class/propal.class.php

@@ -2910,14 +2910,14 @@ class PropaleLigne  extends CommonObject
         $sql.= " ".($this->fk_product?"'".$this->fk_product."'":"null").",";
         $sql.= " '".$this->product_type."',";
         $sql.= " ".($this->fk_remise_except?"'".$this->fk_remise_except."'":"null").",";
-        $sql.= " ".price2num($this->qty).",";
+        $sql.= " '".price2num($this->qty)."',";
         $sql.= " ".price2num($this->tva_tx).",";
         $sql.= " ".price2num($this->localtax1_tx).",";
         $sql.= " ".price2num($this->localtax2_tx).",";
 		$sql.= " '".$this->localtax1_type."',";
 		$sql.= " '".$this->localtax2_type."',";
         $sql.= " ".($this->subprice?price2num($this->subprice):"null").",";
-        $sql.= " ".price2num($this->remise_percent).",";
+        $sql.= " '".price2num($this->remise_percent)."',";
         $sql.= " ".(isset($this->info_bits)?"'".$this->info_bits."'":"null").",";
         $sql.= " ".price2num($this->total_ht).",";
         $sql.= " ".price2num($this->total_tva).",";