ruTorrent: Upgrade to v5.1.5

# ruTorrent v5.1.5
**This is a recommended release for common platforms.**
1. A regression is resolved with RSS feeds not showing up on the **rssurlrewrite** plugin.
2. The layout of the "advanced" tab in the "settings" menu on mobile is improved to reduce scrolling.

## What's Changed
* Put checkboxes in same line with labels by jevenski in Novik/ruTorrent#2834
* Fix rss group not showing by jevenski in Novik/ruTorrent#2835


**Full Changelog**: Novik/ruTorrent@v5.1.4...v5.1.5

Dockerfile

@@ -7,8 +7,8 @@ ARG XMLRPC_VERSION=01.58.00
 ARG MKTORRENT_VERSION=v1.1
 ARG GEOIP2_PHPEXT_VERSION=1.3.1
 
-# v5.1.4
-ARG RUTORRENT_VERSION=699af5f45fef33d8f2b57792ffe7a48d084f2bed
+# v5.1.5
+ARG RUTORRENT_VERSION=25679a45a1e2ca9f7a9e01cab5cc554b8eaa7230
 ARG GEOIP2_RUTORRENT_VERSION=4ff2bde530bb8eef13af84e4413cedea97eda148
 ARG DUMP_TORRENT_VERSION=302ac444a20442edb4aeabef65b264a85ab88ce9