readline: Fix unchecked strdup() by converting to g_strdup()

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

readline.c

@@ -247,14 +247,14 @@ static void readline_hist_add(ReadLineState *rs, const char *cmdline)
     }
     if (idx == READLINE_MAX_CMDS) {
 	/* Need to get one free slot */
-	free(rs->history[0]);
+        g_free(rs->history[0]);
 	memmove(rs->history, &rs->history[1],
 	        (READLINE_MAX_CMDS - 1) * sizeof(char *));
 	rs->history[READLINE_MAX_CMDS - 1] = NULL;
 	idx = READLINE_MAX_CMDS - 1;
     }
     if (new_entry == NULL)
-	new_entry = strdup(cmdline);
+        new_entry = g_strdup(cmdline);
     rs->history[idx] = new_entry;
     rs->hist_entry = -1;
 }