Remove unused variable

src/include/release.sh

 
 _vbump() {
     local rlevel="$1"
-    local lastver   # current from mkit.ini
     local nextver   # after the bump
     _relck git_present
     _relck at_relsrc
     _relck not_dirty
     nextver=$(ini 1value project:version | _bump_version "$rlevel")
-    debug_var lastver nextver
+    debug_var nextver
     $MKIT_DRY && return
     update_version "$nextver" mkit.ini \
       || die "failed to update version in mkit.ini"