Fix dependency in BUILDING.md
btrfs/ioctl.h is now included in libbtrfs-dev instead of btrfs-tools.
Update BUILDING.md Dockerfile to install the correct dependency.
Resolves:
@@ -138,7 +138,7 @@ You can build an image from this `Dockerfile`:
FROM golang
RUN apt-get update && \
- apt-get install -y btrfs-tools libseccomp-dev
+ apt-get install -y libbtrfs-dev libseccomp-dev
```
Let's suppose that you built an image called `containerd/build`. From the
