Meta server: fix status code conversion in chunk server reply path resulted in the status code sign reversal. It looks like that this mainly affected chunk allocation failure detection as the relevant failure detection condition is "less than zero", where in most (all?) of other places affected, the failure conditions are "not equal zero". The effect of the allocation failure mis-detection isn't detrimental, as the undetected chunk allocation manifests itself later on, as write id allocation failure. This bug reduces the failure tolerance in the cases where all chunk servers involved in allocation fail to allocate the chunk, as this would result in no replicas available for "re-allocation" leading to potential write failure if the file was created with no recovery. The bug also reduces failure tolerance in other cases as the initial allocation would result in allocation of less replicas than requested. Though probably most common case of the relevant chunk allocation failures would be "out of space", as the request timeout logic isn't affected by this bug, therefore the practical effect of this bug seems low, or, at best, moderate right now.