Use FUSE_COMPAT_22_INIT_OUT_SIZE always if available.

We return the minor version number 15 to FUSE_INIT since we don't handle
BATCH_FORGET. Thus the kernel does not accept the latest size of
fuse_init_out. Instead we need to use FUSE_COMPAT_22_INIT_OUT_SIZE.

Bug: 32779923
Test: libappfuse_test

Change-Id: I5c979d0e45344ca8adfe3ad3f4a9561442abcb3a
diff --git a/libappfuse/tests/FuseBufferTest.cc b/libappfuse/tests/FuseBufferTest.cc
index 1aacfe3..7f42845 100644
--- a/libappfuse/tests/FuseBufferTest.cc
+++ b/libappfuse/tests/FuseBufferTest.cc
@@ -163,7 +163,7 @@
 
   buffer.HandleInit();
 
-  ASSERT_EQ(sizeof(fuse_out_header) + sizeof(fuse_init_out),
+  ASSERT_EQ(sizeof(fuse_out_header) + FUSE_COMPAT_22_INIT_OUT_SIZE,
             buffer.response.header.len);
   EXPECT_EQ(kFuseSuccess, buffer.response.header.error);
   EXPECT_EQ(static_cast<unsigned int>(FUSE_KERNEL_VERSION),