ZP-1230 Reverting change: WBXMLEncoder->getBodypartsCount() is correct.

WBXMLEncoder->getBodypartsCount() uses count() which returns the count
of elements of bodyparts. Adding one part results in 1 which is correct.
With the patch it stated 2.

Released under the Affero GNU General Public License (AGPL) version 3.

src/lib/core/streamer.php

@@ -300,7 +300,7 @@ class Streamer implements Serializable {
                     if ($encoder->getMultipart() && isset($map[self::STREAMER_PROP]) && $map[self::STREAMER_PROP] == self::STREAMER_TYPE_MULTIPART) {
                         $encoder->addBodypartStream($this->{$map[self::STREAMER_VAR]});
                         $encoder->startTag(SYNC_ITEMOPERATIONS_PART);
-                        $encoder->content($encoder->getBodypartsCount()+1);
+                        $encoder->content($encoder->getBodypartsCount());
                         $encoder->endTag();
                         continue;
                     }