1) "bill" in entry should be an invoice reference, not bill terms reference

2) Fix handling of NULL bill terms reference

git-svn-id: svn+ssh://svn.gnucash.org/repo/gnucash/branches/gda-dev2@17419 57a11ea4-9604-0410-9ed3-97b8803252fd

src/business/business-core/sql/gnc-bill-term-sql.c

@@ -199,7 +199,7 @@ load_billterm_guid( const GncSqlBackend* be, GncSqlRow* row,
 	g_return_if_fail( table_row != NULL );
 
     val = gnc_sql_row_get_value_at_col_name( row, table_row->col_name );
-    if( val == NULL ) {
+    if( val == NULL || !G_VALUE_HOLDS_STRING( val ) || g_value_get_string( val ) == NULL ) {
         pGuid = NULL;
     } else {
         string_to_guid( g_value_get_string( val ), &guid );

src/business/business-core/sql/gnc-entry-sql.c

@@ -83,7 +83,7 @@ static GncSqlColumnTableEntry col_table[] =
 			(QofAccessFunc)gncEntryGetInvTaxTable, (QofSetterFunc)gncEntrySetInvTaxTable },
 	{ "b_acct",        CT_ACCOUNTREF,  0,                   0,        			NULL, ENTRY_BACCT },
 	{ "b_price",       CT_NUMERIC,     0,                   0,        			NULL, ENTRY_BPRICE },
-	{ "bill",          CT_BILLTERMREF,  0,                   0,        			NULL, NULL,
+	{ "bill",          CT_INVOICEREF,  0,                   0,        			NULL, NULL,
 			(QofAccessFunc)gncEntryGetBill, (QofSetterFunc)gncEntrySetBill },
 	{ "b_taxable",     CT_BOOLEAN,     0,                   0,        			NULL, ENTRY_BILL_TAXABLE },
 	{ "b_taxincluded", CT_BOOLEAN,     0,                   0,        			NULL, ENTRY_BILL_TAX_INC },