kb: create a backup of t2g.txt as kb rewrite it

src/nf_modules/kb/main.nf

@@ -37,7 +37,8 @@ process tr2g {
   script:
   """
   t2g.py --gtf ${gtf}
-  uniq t2g_dup.txt > t2g.txt
+  sort -u t2g_dup.txt > t2g.txt
+  rm t2g_dup.txt
   """
 }