setlocalversion: fix version for untaged nontip mercurial revs

The manpage for cut says it will return all lines without the delimiter
unless -s is specified.

When I backed up my mecurial tree to generate modules, I found that the
scm part of localversion was turning up blank.

Signed-off-by: Milton Miller <miltonm@bga.com>
Cc: Michal Marek <mmarek@suse.cz>
Cc: "Michał Górny" <gentoo@mgorny.alt.pl>
Signed-off-by: Michal Marek <mmarek@suse.cz>