father-of-three craig sytsma was mauled to death in michigan last year .
dog owners sebastiano quagliata and wife valbona lucaj agreed to plea deal friday to around 15 years in jail , though judge could add six months .
sytsma was jogging in july 2014 when the two cane corsos attacked him .
he was bitten almost ten times and was ` screaming and begging ' for help .