dmg: make dmg's deterministic

for the fUDIFDataForkChecksum.data and fUDIFMasterChecksum.data structures, it
appears as though only the first int is ever used for checksumming, but the
other bytes are still written to the image. Initialize them so they don't
contain random garbage.

dmg/dmglib.c

@@ -124,6 +124,8 @@ int buildDmg(AbstractFile* abstractIn, AbstractFile* abstractOut) {
 	nsiz = NULL;
     
 	memset(&dataForkToken, 0, sizeof(ChecksumToken));
+	memset(koly.fUDIFMasterChecksum.data, 0, sizeof(koly.fUDIFMasterChecksum.data));
+	memset(koly.fUDIFDataForkChecksum.data, 0, sizeof(koly.fUDIFDataForkChecksum.data));
 	
 	printf("Creating and writing DDM and partition map...\n"); fflush(stdout);
 	
@@ -296,6 +298,8 @@ int convertToDMG(AbstractFile* abstractIn, AbstractFile* abstractOut) {
 	nsiz = NULL;
 	myNSiz = NULL;
 	memset(&dataForkToken, 0, sizeof(ChecksumToken));
+	memset(koly.fUDIFMasterChecksum.data, 0, sizeof(koly.fUDIFMasterChecksum.data));
+	memset(koly.fUDIFDataForkChecksum.data, 0, sizeof(koly.fUDIFDataForkChecksum.data));
 	
 	partitions = (Partition*) malloc(SECTOR_SIZE);