Delete SXT-v25.1.ckan (#1178)

Issue brought up on IRC. SXT 25.1 download is busted because the release no longer exists on GitHub. From what I can tell SXT 25.1 was a prerelease for KSP 1.1, with SXT 25.2 being released shortly after KSP 1.1 went final. Deleting this should make SXT 24 the most recent version for KSP 1.0.5 and users shouldn't get busts trying to install SXT on KSP 1.0.5.

SXT/SXT-v25.1.ckan

@@ -1,35 +0,0 @@
-{
-    "spec_version": "v1.10",
-    "identifier": "SXT",
-    "name": "Stock Extension",
-    "abstract": "Low RAM Stock-a-like expansion using squad models for reference.",
-    "author": "Lack",
-    "license": "CC-BY-NC-SA-4.0",
-    "resources": {
-        "homepage": "http://forum.kerbalspaceprogram.com/index.php?/topic/71992-105-sxt-lacks-stock-extension-sxt-24-09dec15kscv3",
-        "repository": "https://github.com/Signatum/SXT"
-    },
-    "version": "v25.1",
-    "ksp_version": "1.0.5",
-    "depends": [
-        {
-            "name": "FirespitterCore"
-        },
-        {
-            "name": "FirespitterResourcesConfig"
-        },
-        {
-            "name": "ModuleManager"
-        }
-    ],
-    "install": [
-        {
-            "find": "SXT",
-            "install_to": "GameData",
-            "filter": "Thumbs.db"
-        }
-    ],
-    "download": "https://github.com/Signatum/SXT/releases/download/v25.1/SXT25pre.zip",
-    "download_size": 36580984,
-    "x_generated_by": "netkan"
-}