BUG/MINOR: cfgparse-global: remove tune.fast-forward from common_kw_list

Remove tune.fast-forward from common_kw_list. It was replaced by
'tune.disable-fast-forward' and it's no longer present in "if..else if.."
parser from cfg_parse_global(). Otherwise, it may be shown as the best-match
keyword for some tune options, which is now wrong.

Should be backported in versions 2.9 and 3.0.

src/cfgparse-global.c

@@ -33,8 +33,7 @@ int cluster_secret_isset;
 static const char *common_kw_list[] = {
 	"global", "busy-polling", "set-dumpable",
 	"insecure-fork-wanted", "insecure-setuid-wanted", "nosplice",
-	"nogetaddrinfo", "noreuseport",
-	"tune.fast-forward", "uid", "gid",
+	"nogetaddrinfo", "noreuseport", "uid", "gid",
 	"external-check", "user", "group", "maxconn",
 	"ssl-server-verify", "maxconnrate", "maxsessrate", "maxsslrate",
 	"maxcomprate", "maxpipes", "maxzlibmem", "maxcompcpuusage", "ulimit-n",