vfs: avoid memsetting one byte too many in MemoryMappedFile::trap
vfs: avoid memsetting one byte too many in MemoryMappedFile::trap

jmolloy/pedigree,jmolloy/pedigree,jmolloy/pedigree,jmolloy/pedigree,jmolloy/pedigree,jmolloy/pedigree,jmolloy/pedigree