processgroup: close directories opened by removeAllProcessGroups()

removeAllProcessGroups and removeUidProcessGroups were calling
opendir, but never called closedir.  This would leave a leaked
file descriptor for every /acct/uid_* directory that existed
at boot.

Change-Id: Ia08eccd42d6ad7a6c1c78402519ac2e53b4fc83a
1 file changed