Fixed seafile-controller.c (corrected pid directory location) and seafil...

...e-admin (bug in is_running also reported false positives in the shape of cmd line arguments of the same name)
> Why do you want to store the pids there and not in the seafile-server subdir?

The pids/ folder is not placed under seafile-data folder, so that multiple servers may share the same copy of seafile-data/ folder through NFS.