fuse2fs: fix error bailout in op_create

fuse2fs: fix error bailout in op_create

Tim Woodall pointed out that op_create returns garbage error codes if
the ext2fs_extent_open2 in op_create fails.  Worse than that, it also
neglects to drop the bfl and leaks temp_path.  Let's fix all that.

Cc: linux-ext4@vger.kernel.org # v1.43
Fixes: 81cbf1ef4f5dab ("misc: add fuse2fs, a FUSE server for e2fsprogs")
Reported-by: Tim Woodall <debianbugs@woodall.me.uk>
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Signed-off-by: Theodore Ts'o <tytso@mit.edu>