collectd: update to 5.7.2

* update collectd to 5.7.2
* drop backported upstream patch that is now in release
* refresh patches

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

utils/collectd/patches/600-fix-libmodbus-detection.patch

@@ -18,7 +18,7 @@ Reversed patch to be applied:
 
 --- a/configure.ac
 +++ b/configure.ac
-@@ -3186,7 +3186,7 @@ then
+@@ -3278,7 +3278,7 @@ then
  	SAVE_CPPFLAGS="$CPPFLAGS"
  	CPPFLAGS="$CPPFLAGS $with_libmodbus_cflags"