patch 8.0.0468: after aborting an Ex command g< does not work

Problem:    After aborting an Ex command g< does not work. (Marcin
            Szamotulski)
Solution:   Postpone clearing scrollback messages to until the command line
            has been entered.  Also fix that the screen isn't redrawn if after
            g< the command line is cancelled.
diff --git a/src/misc2.c b/src/misc2.c
index 522fcb6..357511d 100644
--- a/src/misc2.c
+++ b/src/misc2.c
@@ -970,7 +970,7 @@
 	    break;
 	releasing = TRUE;
 
-	clear_sb_text();	      /* free any scrollback text */
+	clear_sb_text(TRUE);	      /* free any scrollback text */
 	try_again = mf_release_all(); /* release as many blocks as possible */
 
 	releasing = FALSE;
@@ -1148,7 +1148,7 @@
 # ifdef FEAT_DIFF
     diff_clear(curtab);
 # endif
-    clear_sb_text();	      /* free any scrollback text */
+    clear_sb_text(TRUE);	      /* free any scrollback text */
 
     /* Free some global vars. */
     vim_free(username);