collectd: Update to 5.4.1

-update collectd to the current release 5.4.1
-fix sigrok glib check (upstream patch after 5.4.1)

Note:
Changes are required also to luci-statistics in Luci source.
Patch in http://patchwork.openwrt.org/patch/5303/

Signed-off-by: Hannu Nyman <hannu.nyman@iki.fi>

utils/collectd/patches/140-fix-fqdnlookup.patch

@@ -0,0 +1,11 @@
+--- a/src/configfile.c
++++ b/src/configfile.c
+@@ -105,7 +105,7 @@ static cf_global_option_t cf_global_opti
+ 	{"BaseDir",     NULL, PKGLOCALSTATEDIR},
+ 	{"PIDFile",     NULL, PIDFILE},
+ 	{"Hostname",    NULL, NULL},
+-	{"FQDNLookup",  NULL, "true"},
++	{"FQDNLookup",  NULL, "false"},
+ 	{"Interval",    NULL, NULL},
+ 	{"ReadThreads", NULL, "5"},
+ 	{"WriteThreads", NULL, "5"},