ZO-21 ignore cases of header.

src/backend/zarafa/zarafa.php

@@ -433,7 +433,7 @@ class BackendZarafa implements IBackend, ISearchProvider {
 
         // Acacia ZO-6: grep for the OL header and set flags accordingly.
         // The header has the values verb/message-source-key/folder-source-key
-        if (preg_match("/X-Push-Flags: (\d{3})\/([\da-f]+)\/([\da-f]+)/", $sm->mime, $ol_flags)) {
+        if (preg_match("/X-Push-Flags: (\d{3})\/([\da-f]+)\/([\da-f]+)/i", $sm->mime, $ol_flags)) {
             // "reply" and "reply-all" are handled as "reply"
             if ($ol_flags[1] == 102 || $ol_flags[1] == 103) {
                 $sm->replyflag = true;