Add check to ensure finfo_open works in ensure_file function

MD_STD.php

@@ -397,13 +397,15 @@ public static function ensure_file(string $filepath, array $accepted_mimetype =
             return;
         }
 
-        $finfo = \finfo_open(FILEINFO_MIME_TYPE);
+        if (!($finfo = \finfo_open(FILEINFO_MIME_TYPE))) {
+            throw new Exception("Cannot open finfo context");
+        }
         if (!($mime_type = finfo_file($finfo, $filepath))) {
             throw new MDWrongFileType("Cannot get mime type of file: " . basename($filepath));
         }
         \finfo_close($finfo);
 
-        if (!\in_array($mime_type, $accepted_mimetype)) {
+        if (!\in_array($mime_type, $accepted_mimetype, true)) {
             throw new MDWrongFileType("Incorrect mime type of file " . \basename($filepath) . ". Mime type is " . \mime_content_type($filepath) . ", accepted any of ['" . \implode("', '", $accepted_mimetype) . "']");
         }