zstreamdump needs to initialize fletcher 4 support

Otherwise, the checksum function pointer isn't initialized.

Reviewed-by: Brian Behlendorf <behlendorf1@llnl.gov>
Signed-off-by: Tim Chase <tim@chase2k.com>
Closes #5411

cmd/zstreamdump/zstreamdump.c

@@ -265,6 +265,7 @@ main(int argc, char *argv[])
 		exit(1);
 	}
 
+	fletcher_4_init();
 	send_stream = stdin;
 	while (read_hdr(drr, &zc)) {
 
@@ -618,6 +619,7 @@ main(int argc, char *argv[])
 		pcksum = zc;
 	}
 	free(buf);
+	fletcher_4_fini();
 
 	/* Print final summary */