This avoids pulling in glibc & co. Fixes a regression introduced in
2f861edf5cf5118ad560737343312c9a5efe5b2f (the 'unionfsctl' executable
did not exist in unionfs-fuse 0.26).
* gnu/packages/linux.scm (unionfs-fuse/static)[arguments]
<post-install>: Remove 'unionfsctl' binary.