Description:
------------
I'm using OCI8 1.1.1, and I think that ocierror function  
must keep the last ocurred error for more than one call to  
ocierror. 
 
I have made some tests with SQLite and MySQL, and this 
feature that I request is implemented by these database 
modules. 

Reproduce code:
---------------
<?php
	$conn = ocilogon('user', 'pass', 'db');
	if (!$conn) die('Not possible to connect to database');
        // There is a constraint here
	$query = 'DELETE FROM SGR_ATIVIDADE WHERE CDATIVIDADE=2';
	$stmt  = ociparse($conn, $query);
	$ret   = ociexecute($stmt);

	if ($ret) echo 'Atividade deleted.';
	else {
		$cnt = 10;
		while ($cnt-- > 0) {
			$aError = ocierror($stmt);
			echo (10-$cnt) .' -> '.$aError['message'] ."\n";
		}
	}

	ocilogoff($conn);
?>

Expected result:
----------------
1 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found  
2 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found 
3 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found 
4 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found 
5 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found 
6 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found 
7 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found 
8 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found 
9 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found 
10 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES)  
violated - child record found 

Actual result:
--------------
1 -> ORA-02292: integrity constraint (SISCORP.ATV_GRPPES) 
violated - child record found 
2 -> 
3 -> 
4 -> 
5 -> 
6 -> 
7 -> 
8 -> 
9 -> 
10 ->