patch 8.2.3530: ":buf \{a}" fails while ":edit \{a}" works

Problem:    ":buf \{a}" fails while ":edit \{a}" works.
Solution:   Unescape "\{". (closes #8917)
diff --git a/src/evalfunc.c b/src/evalfunc.c
index 4abbdb9..0843824 100644
--- a/src/evalfunc.c
+++ b/src/evalfunc.c
@@ -3886,7 +3886,7 @@
 	return;
 
     rettv->vval.v_string = vim_strsave_fnameescape(
-					   tv_get_string(&argvars[0]), FALSE);
+					 tv_get_string(&argvars[0]), VSE_NONE);
     rettv->v_type = VAR_STRING;
 }