fuse: move conflict opcodes into linux specific build

`CAP_SETXATTR_EXT,CAP_INIT_EXT,CAP_INIT_RESERVED` opcodes conflicts with
osxfuse `CAP_CASE_INSENSITIVE,CAP_VOL_RENAME,CAP_XTIMES` opcodes,
that's causing panic, so it should be moved into linux specific build.

Change-Id: I0916ea0bd2c169a0aa1f654ef015799fa0e5084e

fuse/print.go

@@ -49,9 +49,6 @@ var (
 		CAP_MAP_ALIGNMENT:       "MAP_ALIGNMENT",
 		CAP_SUBMOUNTS:           "SUBMOUNTS",
 		CAP_HANDLE_KILLPRIV_V2:  "HANDLE_KILLPRIV_V2",
-		CAP_SETXATTR_EXT:        "SETXATTR_EXT",
-		CAP_INIT_EXT:            "INIT_EXT",
-		CAP_INIT_RESERVED:       "INIT_RESERVED",
 		CAP_SECURITY_CTX:        "SECURITY_CTX",
 		CAP_HAS_INODE_DAX:       "HAS_INODE_DAX",
 		CAP_CREATE_SUPP_GROUP:   "CREATE_SUPP_GROUP",

fuse/print_linux.go

@@ -13,6 +13,9 @@ func init() {
 	openFlagNames.set(syscall.O_DIRECT, "DIRECT")
 	openFlagNames.set(syscall.O_LARGEFILE, "LARGEFILE")
 	openFlagNames.set(syscall_O_NOATIME, "NOATIME")
+	initFlagNames.set(CAP_SETXATTR_EXT, "SETXATTR_EXT")
+	initFlagNames.set(CAP_INIT_EXT, "INIT_EXT")
+	initFlagNames.set(CAP_INIT_RESERVED, "INIT_RESERVED")
 }
 
 func (a *Attr) string() string {

fuse/types.go

@@ -305,9 +305,6 @@ const (
 	CAP_MAP_ALIGNMENT       = (1 << 26)
 	CAP_SUBMOUNTS           = (1 << 27)
 	CAP_HANDLE_KILLPRIV_V2  = (1 << 28)
-	CAP_SETXATTR_EXT        = (1 << 29)
-	CAP_INIT_EXT            = (1 << 30)
-	CAP_INIT_RESERVED       = (1 << 31)
 
 	/* bits 32..63 get shifted down 32 bits into the Flags2 field */
 	CAP_SECURITY_CTX      = (1 << 32)

fuse/types_linux.go

@@ -15,6 +15,16 @@ const (
 	EREMOTEIO = Status(syscall.EREMOTEIO)
 )
 
+// To be set in InitIn/InitOut.Flags.
+//
+// This flags conflict with https://github.com/osxfuse/fuse/blob/master/include/fuse_common.h
+// and should be used only on Linux.
+const (
+	CAP_SETXATTR_EXT  = (1 << 29)
+	CAP_INIT_EXT      = (1 << 30)
+	CAP_INIT_RESERVED = (1 << 31)
+)
+
 type Attr struct {
 	Ino  uint64
 	Size uint64