Drop the use of --always to git-describe

This is a partial revert of c435f06b30,
since it didn't actually fix the original problem with shallow clones.
It returns just a hash, not something we (currently) can extract as a
version string in the form things are expecting.

update_version

@@ -34,8 +34,7 @@ fi
 # -dirty from files that have been touched but are not actually altered in the
 # working dir.
 GIT_VERSION=$(cd "$SRCDIR" && git status > /dev/null 2>&1 \
-                           && git describe --tags --match 'v*' \
-                                           --always --dirty 2> /dev/null)
+                           && git describe --tags --match 'v*' --dirty 2> /dev/null)
 GIT_VERSION=${GIT_VERSION#v}
 
 if [ -n "$GIT_VERSION" ]; then