Bug 41063: Run "file $keyring" in tools/keyring/list-all-keyrings

(cherry picked from commit 0fe87b4a)

tools/keyring/list-all-keyrings

@@ -6,5 +6,6 @@ set -e
 cd $(dirname "$0")/../..
 for keyring in ./keyring/*.gpg
 do
+    file "$keyring"
     gpg --no-auto-check-trustdb --list-options show-unusable-subkeys,show-keyring --no-default-keyring --list-keys --keyring "$keyring"
 done