bug #3559: Set free_mb = 0 when limit > used
bug #3559: Set free_mb = 0 when limit > used

(cherry picked from commit bd45b9776a75b24257d8cd2339d7027e6fdb8850)

Terradue/one,Terradue/one,Terradue/one,Terradue/one,Terradue/one,Terradue/one,Terradue/one,Terradue/one