clean up screen and tail_log references

Change-Id: I6bcfa09931ed1f70e071ccb16688c15c7ef2898f
diff --git a/lib/nova b/lib/nova
index bd6695a..5b78972 100644
--- a/lib/nova
+++ b/lib/nova
@@ -882,7 +882,7 @@
     export PATH=$old_path
 }
 
-# start_nova() - Start running processes, including screen
+# start_nova() - Start running processes
 function start_nova_rest {
     # Hack to set the path for rootwrap
     local old_path=$PATH
@@ -999,7 +999,7 @@
     done
 }
 
-# stop_nova() - Stop running processes (non-screen)
+# stop_nova() - Stop running processes
 function stop_nova {
     stop_nova_rest
     stop_nova_conductor