[FS#988] Procd does not respect a user's groups when using parameter user

[LEDE Bugs]

The following task is now closed:

FS#988 - Procd does not respect a user's groups when using parameter user
User who did this - Yousong Zhou (yousong)

Reason for closing: Fixed
Additional comments about closing: Fixed with git.lede-project.org/b2aa820b48add74b97e0eab993ede648c43e85db

More information can be found at the following URL:
https://bugs.lede-project.org/index.php?do=details&task_id=988