patch 8.0.0887: can create a logfile in the sandbox

Problem:    Can create a logfile in the sandbox.
Solution:   Disable ch_logfile() in the sandbox. (Yasuhiro Matsumoto)

src/evalfunc.c

@@ -1930,6 +1930,9 @@ f_ch_logfile(typval_T *argvars, typval_T *rettv UNUSED)
     char_u *opt = (char_u *)"";
     char_u buf[NUMBUFLEN];
 
+    /* Don't open a file in restricted mode. */
+    if (check_restricted() || check_secure())
+	return;
     fname = get_tv_string(&argvars[0]);
     if (argvars[1].v_type == VAR_STRING)
 	opt = get_tv_string_buf(&argvars[1], buf);

src/version.c

@@ -769,6 +769,8 @@ static char *(features[]) =
 
 static int included_patches[] =
 {   /* Add new patch number below this line */
+/**/
+    887,
 /**/
     886,
 /**/