debian: fix typo in fuse2fs.postrm which breaks a /usr-move mitigation

debian: fix typo in fuse2fs.postrm which breaks a /usr-move mitigation

A space was accidenally introduced into the fuse2fs.postrm which
breaks the /usr-move replacement of fusext2 from an older legacy
package that had been abandoned upstream.  Specifically, what was
broken was the cleanup of the protective diversions:

Unpacking fuse2fs (1.47.2-2) over (1.47.2-1+b1) ...
/var/lib/dpkg/info/fuse2fs.postrm: 6: test: failed-upgrade: unexpected operator

Addresses-Debian-Bug: #1107595
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
(cherry picked from commit b539a0370777feaa5652fd42d32fc66b2cea8788)