patch 8.0.0867: job and channel in a dict value not quoted

Problem:    When using a job or channel value as a dict value, when turning it
            into a string the quotes are missing.
Solution:   Add quotes to the job and channel values. (Yasuhiro Matsumoto,
            closes #1930)
diff --git a/src/list.c b/src/list.c
index 2fccbae..b593f71 100644
--- a/src/list.c
+++ b/src/list.c
@@ -740,7 +740,7 @@
     for (item = l->lv_first; item != NULL && !got_int; item = item->li_next)
     {
 	s = echo_string_core(&item->li_tv, &tofree, numbuf, copyID,
-					   echo_style, restore_copyID, FALSE);
+				      echo_style, restore_copyID, !echo_style);
 	if (s == NULL)
 	    return FAIL;