MDL-67034 adodb: php74 fix (curly braces) for the AdoDB lib

lib/adodb/drivers/adodb-oci8po.inc.php

@@ -120,7 +120,7 @@ class ADODB_oci8po extends ADODB_oci8 {
 			/*
 			* find the next character of the string
 			*/
-			$c = $sql{$i};
+			$c = $sql[$i];
 
 			if ($c == "'" && !$inString && $escaped==0)
 				/*

lib/adodb/readme_moodle.txt

@@ -30,5 +30,6 @@ Our changes:
  * Removed random seed initialization from lib/adodb/adodb.inc.php:216 (see 038f546 and MDL-41198).
  * MDL-52286 Added muting erros in ADORecordSet::__destruct().
    Check if fixed upstream during the next upgrade and remove this note. (8638b3f1441d4b928)
+ * MDL-67034 Fixes to make the library php74 compliant.
 
 skodak, iarenaza, moodler, stronk7, abgreeve, lameze, ankitagarwal, marinaglancy