verify: handle corrupt verified.json

verified.json can get quite large on verification.f-droid.org, and for some
unknown reason, it sometimes corrupts it when writing it out.  All the data
is already available in all the other JSON files, so this just automatically
reconstructs it.  Its a hack, but it took me much less time than I've
already spent trying to troubleshoot why it writes out corrupt verified.json.

tests/org.fdroid.fdroid_1019051.apk.json

@@ -0,0 +1,43 @@
+{
+  "1708238023.6572325": {
+    "diffoscope": {
+      "Available-in-Debian-packages": [
+        "coreboot-utils",
+        "ghc",
+        "libxmlb-dev",
+        "radare2"
+      ],
+      "External-Tools-Required": [
+        "cbfstool",
+        "ghc",
+        "lipo",
+        "otool",
+        "radare2",
+        "xb-tool"
+      ],
+      "Missing-Python-Modules": [
+        "pypdf",
+        "r2pipe"
+      ],
+      "VERSION": "240"
+    },
+    "local": {
+      "file": "unsigned/org.fdroid.fdroid_1019051.apk",
+      "packageName": "org.fdroid.fdroid",
+      "sha256": "0eec78236ec5ebb8f416c611717bd659b75d2b6600ef71a50c922efc99dbdca2",
+      "timestamp": 1708238023.6572325,
+      "versionCode": 1019051,
+      "versionName": "1.19.1"
+    },
+    "remote": {
+      "file": "tmp/org.fdroid.fdroid_1019051.apk",
+      "packageName": "org.fdroid.fdroid",
+      "sha256": "162cb14b93bd9b665fff4256b4fc91cfe75fb72335a02b1d0febe606220b50f4",
+      "timestamp": 1715356428.522411,
+      "versionCode": 1019051,
+      "versionName": "1.19.1"
+    },
+    "url": "https://f-droid.org/repo/org.fdroid.fdroid_1019051.apk",
+    "verified": true
+  }
+}