Set @gitolite_ssh_fingerprint to nil when flushing Settings cache

Author: root

Diff for: lib/redmine_git_hosting/config/gitolite_base.rb

@@ -18,6 +18,7 @@ def check_cache
         @gitolite_home_dir = nil
         @mirroring_keys_installed = nil
         @mirroring_public_key = nil
+        @gitolite_ssh_fingerprint = nil
       end