fuse: don't set flagname keyed by syscall.O_LARGEFILE

On amd64, syscall.O_LARGEFILE is 0x0, making it be ignored as a
key. However, the kernel always passes 0x8000 to the FUSE server for
the OPEN call.

The previous behavior causes crashes on 386, because the flagname is
added twice.

Change-Id: Ibabcdfef4d90e4fa4d02963d45a4d4cf2cba1ea2

fuse/print.go

@@ -64,6 +64,8 @@ var (
 		int64(syscall.O_NONBLOCK): "NONBLOCK",
 		int64(os.O_SYNC):          "SYNC",
 		int64(os.O_TRUNC):         "TRUNC",
+		// syscall.O_LARGEFILE is 0x0 on x86_64, but the
+		// kernel supplies 0x8000 anyway.
 		0x8000:                     "LARGEFILE",
 		int64(syscall.O_CLOEXEC):   "CLOEXEC",
 		int64(syscall.O_DIRECTORY): "DIRECTORY",

fuse/print_linux.go

@@ -11,7 +11,6 @@ import (
 
 func init() {
 	openFlagNames.set(syscall.O_DIRECT, "DIRECT")
-	openFlagNames.set(syscall.O_LARGEFILE, "LARGEFILE")
 	openFlagNames.set(syscall_O_NOATIME, "NOATIME")
 	initFlagNames.set(CAP_NO_OPENDIR_SUPPORT, "NO_OPENDIR_SUPPORT")
 	initFlagNames.set(CAP_EXPLICIT_INVAL_DATA, "EXPLICIT_INVAL_DATA")