Description:
------------
Calling openssl_public_encrypt causes an "error:0906D06C:PEM routines:PEM_read_bio:no start line" to be returned from openssl_error_string, even though the function passes and returns an encrypted string

This has become apparent when using PDO with SSL, as the openssl_error_string drops the connection.

I think some work was done on the in Bug #69524, however the issue still appears to be in place, at least for the openssl_public_encrypt function

Test script:
---------------
<?php

$key = "-----BEGIN PUBLIC KEY-----
MIGfMA0GCSqGSIb3DQEBAQUAA4GNADCBiQKBgQDLXp6PkCtbpV+P1gwFQWH6Ez0U
83uEmS8IGnpeI8Fk8rY/vHOZzZZaxRCw+loyc342qCDIQheMOCNm5Fkevz06q757
/oooiLR3yryYGKiKG1IZIiplmtsC95oKrzUSKk60wuI1mbgpMUP5LKi/Tvxes5Pm
kUtXfimz2qgkeUcPpQIDAQAB
-----END PUBLIC KEY-----";
$message = '123';
$passed = openssl_public_encrypt($message, $response, $key);
echo (($passed) ? "Function Passed" : "Function Failed") . PHP_EOL;
echo ((is_null($response)) ? "No Result Returned" : "Result Returned Successfully") . PHP_EOL;
if ($error = openssl_error_string()) {
    echo "Error Returned: ";
    echo $error;
}

Expected result:
----------------
The script should either display 

Function Passed
Result Returned

or it should display

Function Failed
No Result Returned
Error Returned: ${an openssl error string}

Actual result:
--------------
Function Passed
Result Returned Successfully
Error Returned: error:0906D06C:PEM routines:PEM_read_bio:no start line