c2k: include lemma only if !='_' (unless token is also '_')

Change-Id: Id1fd52a61177d47286bad858a561ccdc7c2df64e
diff --git a/script/conllu2korapxml b/script/conllu2korapxml
index b4aa17a..1fdad0d 100755
--- a/script/conllu2korapxml
+++ b/script/conllu2korapxml
@@ -142,6 +142,7 @@
      <fs>
       <f name="pos">$parsed[3]</f>
 );
+      $morpho .= qq(      <f name="lemma">$parsed[2]</f>\n) if($parsed[2] ne "_" || $parsed[1] eq '_');
       $morpho .= qq(      <f name="msd">$parsed[5]</f>\n) if($parsed[5] ne "_");
       if($parsed[9] ne "_") {
         if ($parsed[9] =~ /[0-9.e]+/) {